A Domino Palladium-Catalyzed Cyclization: One-Pot Synthesis of 4b

Article pubs.acs.org/joc

A Domino Palladium-Catalyzed Cyclization: One-Pot Synthesis of 4bAlkyl-10-phenyl-4b,5-dihydroindeno[2,1‑a]indenes via Carbopalladation Followed by C−H Activation Karu Ramesh and Gedu Satyanarayana* Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi 502 285, Sangareddy, Telangana India S Supporting Information *

ABSTRACT: An effective domino one-pot [Pd]-catalysis for the construction of novel tetracyclic compounds was described. This process involved in the construction of three C−C bonds from simple and readily available 1-bromo-2isopropenylbenzenes and internal alkynes. A variety of fused tetracyclic dihydroindeno-indenes were accomplished.

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INTRODUCTION The development of domino synthetic processes are vital in organic synthesis1,2 as they are the most useful methods for the efficient synthesis of organic molecules in a highly stereoselective manner. In this context, the transition-metal-catalyzed annulations of internal alkynes have received much attention to access complex cyclic frameworks.3 Among them, [Pd]catalyzed domino cyclizations have been widely investigated.4 Consequently, remarkable contributions have been made by the research group of Larock toward the annulation processes of internal alkynes for the synthesis of a variety of cyclic systems.5 In 2012, Lautens et al. established an interesting palladiumcatalyzed domino reaction of 1-iodo-2-isopropenylbenzenes with internal alkyne via dual insertion followed by a C−I reductive elimination for the synthesis of substituted carboiodinated indenes.6 Very recently, Sanz and co-workers reported the gold(I)-catalyzed cycloisomerization of β,β-diaryl-o-(alkynyl)-styrenes affording dihydroindeno[2,1-a]indenes via a formal [4 + 1] cycloaddition.7 In continuation of our research interests on the development of domino transformations,8 we envisioned that the 1-bromo-2isopropenylbenzenes9 in the presence of an appropriately designed palladium-catalyst would undergo first intermolecular insertion onto the triple bond of internal alkynes followed by a second intramolecular insertion into the olefinic bond (i.e., the first cyclization) that leads to carbo-palladation of indenes. Further, we envisaged that with an appropriate palladiumcatalyst, these carbo-palladized indenes would in turn be feasible for the final cyclization (i.e., the second cyclization) with the aromatic ring of internal acetylenes through C−H activation10 to furnish the novel 4b-alkyl-10-phenyl-4b,5dihydroindeno[2,1-a]indenes 3. To the best of our knowledge, there are no reports on the synthesis of 4b-alkyl-10-phenyl© 2017 American Chemical Society

4b,5-dihydroindeno[2,1-a]indenes 3 by using palladium catalysis, starting from less reactive 1-bromo-2-isopropenylbenzenes 1. While, all other earlier reports include the usage of more reactive 1-iodo-2-isopropenylbenzenes led to the synthesis of different compounds other than the tetracyclic systems 3 depending on the reaction conditions.6,11 Herein, we report a palladium-catalyzed domino process comprising intermolecular alkyne insertion and intramolecular alkene insertion followed by intramolecular C−H activation for the synthesis of tetracyclics 3. This strategy enabled the formation of three new C−C bonds in one-pot and resulted in analogous polysubstituted 4b-alkyl-10-phenyl-4b,5-dihydroindeno[2,1-a]indenes 3.

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RESULTS AND DISCUSSION To begin with, initially, we have chosen 1-bromo-2isopropenylbenzene 1a and diphenyl acetylene 2a as model substrates in order to optimize the reaction conditions, and the outcomes are depicted in Table 1. No detectable product was obtained with the Pd(OAc)2 (5 mol %)/BINAP (10 mol %), base NaHCO3 in DMF at 125 °C (Table 1, entry 6). Interestingly, in toluene, the anticipated product 3aa was obtained in poor yield (Table 1, entry 7). It was evident that the presence of quaternary ammonium salt (QX; X = Cl, Br, I, and HSO4) enhances catalytic activity of palladium catalysis.12 Therefore, the reaction was executed with the quaternary ammonium salts (Br and I), however, afforded 3aa, in slightly improved yield (Table 1, entries 8−9). Gratifyingly, the reaction performed with the additive benzyltriethylammonium chloride (TEBAC) furnished the product 3aa in 68% yield Received: February 1, 2017 Published: March 30, 2017 4254

DOI: 10.1021/acs.joc.7b00254 J. Org. Chem. 2017, 82, 4254−4264

Article

The Journal of Organic Chemistry Table 1. Optimization Studies for the Formation of 4b-Methyl-10-phenyl-4b,5-dihydroindeno[2,1-a]indene 3aaa,b

entry

ligand

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

1,10-Phen TEBAC PPh3 BINAP BINAP BINAP BINAP BINAP BINAP BINAP BINAP BINAP BINAP BINAP BINAP BINAP AsPh3 BINAP BINAP Xanthphos DMAP

additive (equiv)

TBAI (1) TBAB (1) TEBAC (1) TEBAC (0.5) TEBAC (2) TEBAC (1) TBAI (1)

base

solvent (mL)

temp (°C)

time (h)

yield 3aa

K2CO3 NaoAc NaoAc NaoAc K2CO3 NaHCO3 K2CO3 K2CO3 K2CO3 K2CO3 K2CO3 K2CO3 K2CO3 K2CO3 K2CO3 Cs2CO3 K2CO3 K2CO3 K2CO3 K2CO3 K2CO3

DMF DMF DMF DMF DMF DMF toluene toluene toluene toluene toluene toluene xylene xylene xylene xylene xylene DMA DMA DMA H2O

140 100 100 120 120 125 120 140 140 140 140 140 140 140 140 140 140 140 160 160 120

24 36 36 36 60 36 40 36 36 36 36 36 36 20 36 36 24 36 36 36 36

c c c c c c 12% 20% 20% 68% 48% 69% 48% 10% 13% c d 15% 15% c d

a

Unless otherwise mentioned, all the reactions were carried out by using 49.3 mg (0.25 mmol) of 1-bromo-2-isopropenylbenzene 1a, 111.2 mg (0.62 mmol) of 1,2-diphenylethyne 2a, base (2 mmol, 4 equiv), Pd(OAc)2 (5 mol %), ligand (10 mol %), additive (1 equiv), and solvent (0.5 mL). b Chromatographically isolated yields of pure product 3aa. cNo significant spot was observed on TLC; neither the starting material was recovered nor any product was isolated. dStarting material recovered. Abbreviations: TEBAC = benzyltriethylammonium chloride; BINAP = [2,2′bis(diphenylphosphino)-1,1′-binaphthyl]; DMAP = 4-dimethylaminopyridine; TBAI = tetra-n-butylammonium iodide; TBAB = tetra-nbutylammonium bromide; DMF = N,N-dimethylmethanamide; DMA = N,N-dimethylacetamide.

(Table 1, entry 10). Also, the reaction was performed with varying amounts of TEBAC. With the 0.5 equiv of TEBAC, the product 3aa yield was moderate (Table 1, entry 11), while 2 equiv of TEBAC afforded the product 3aa, in more or less same yield to that obtained with 1 equiv of TEBAC (Table 1, entry 12). Other variations were found inferior to deliver 3aa (Table 1, entries 1−6 and 13-21). With these optimized reaction parameters (Table 1, entry 10), to check the applicability of the method, the reaction has been explored with 1-bromo-2-isopropenylbenzenes 1a-d and other internal alkynes 2a-k. Gratifyingly, the reaction showed good substrate scope and delivered the tetracyclic compounds 3 (Table 2). Notably, the domino cyclization was smooth with symmetrical diaryl alkynes 2a-k bearing different functional groups, such as ranging from electron donating to electron deactivating moieties on the aromatic rings (i.e., Me, OMe, F, and CF3 substituents). Delightfully, the substituent at the meta position on aromatic rings of diaryl alkynes (2c, 2e, 2j, and 2k) furnished the single regioisomeric products (3ac, 3ae, 3aj, and 3ck), and the final cyclization has selectively happened at the para position to the substituent. This may be due to the fact that palladium catalysis is steric sensitive, and hence, the final C−H activation took place at relatively less hindered para position to the substituent. The reaction was also amenable with 1-iodo-2-isopropenylbenzene 1j and furnished the product 3aa in fair yield. Also, the reaction was successful with 1-chloro-

2-isopropenylbenzene 1i, albeit furnished the product 3aa, in moderate yield. Delightfully, the reaction was also compatible with bis(thienyl)acetylene 2h (Table 2, 3ah). Significantly, the reaction was also amenable with other ortho-bromostyrenes, such as, 1-bromo-2-isopropenylbenzene 1b, 1-bromo-2-(1propylvinyl)benzene 1c and 1-bromo-2-(1-isopropylvinyl)benzene 1d, and afforded the corresponding tetracyclic products 3ba-da (Table 2). Whereas, the reaction with other internal alkynes, such as, prop-1-ynylbenzene 2m and ethyl methyl 3-phenylpropiolate 2n was inconclusive (i.e., complex mixtures were observed even at different temperatures). Also, it is worth noting that the reaction was unsuccessful with 1methyl-2-[(2-methylphenyl)ethynyl]benzene 2l. On the other hand, the reaction with β-substituted styrene [1-bromo-2-[1methylpent-1-enyl]benzene] was unsuccessful (i.e., neither the starting material nor the product was obtained). The chemical structures of 3 were further confirmed by the single crystal Xray diffraction analysis of 3ac (see the Supporting Information for X-ray data [CCDC 1508676]). The reaction with unsymmetrical alkyne 2g under standard reaction conditions (i.e., at 140 °C) afforded the regioisomeric mixture of products 3ag and 3ag′. Even at relatively low temperature 100 °C, the regioselectivity was not improved. On the other hand, the reaction of 1a with unsymmetrical alkyne 2i under standard conditions was inconclusive (i.e., at 140 °C, neither the starting material nor the product was isolated). 4255


Article

The Journal of Organic Chemistry Table 2. Synthesis of 4b-Alkyl-10-phenyl-4b,5-dihydroindeno[2,1-a]indenes 3a,b,c,de

a Reaction conditions: 1-bromo-2-alkylidenebenzenes 1a-d (0.25 mmol), diaryl acetylenes 2a-k (0.62 mmol), Pd(OAc)2 (5 mol %), BINAP (10 mol %), TEBAC (1 equiv), K2CO3 (4 equiv), toluene (0.5 mL), 140 °C, 36−48 h. bYields in the parentheses are isolated yields of chromatographically pure products. cThe first alphabet of products 3aa-da refers to the 1-bromo-2-alkylidenebenzenes, while the second letter indicates the alkynes. d Yield of the product when halogen is iodide. eYield of the product when halogen is chloride.

However, we were pleased to find the formation of single regioisomeric product 3ai and 3ei at relatively low temperature 100 °C (Table 3). To further demonstrate the scope and generality of the method, 1-bromo-2-isopropenylbenzenes 1 with additional functionality on the aromatic ring were also investigated. In general, the reaction was quite successful with substituted orthobromostyrenes comprising methoxy and benzyloxy groups and furnished the desired tetracyclic products 3ea-ha (Table 4). Also, the protocol was compatible with electron deactivating fluoro substituent on the styrene aromatic ring (Table 4, 3ha). Notably, the reaction also showed good functional group tolerance with regards to the functionality on the aromatic rings of diaryl alkynes 2a-j (Table 4). The plausible reaction mechanism for the formation of 4balkyl-10-phenyl-4b,5-dihydroindeno[2,1-a]indenes 3 is described in Scheme 1. Thus, the initial insertion of Pd0 catalyst onto the C−Br bond of 1 yields aryl-PdII species A. Intermolecular insertion of the aryl-PdII species A upon to the alkyne triple bond furnishes the alkenyl-PdII species B, which on intramolecular insertion into the alkene bond generates C(sp3)-PdII−Br indene intermediate C. Finally, subsequent intramolecular C(sp2)-H activation by C(sp3)PdII−Br species C affords the tetracyclic six membered C(sp3)PdII−C(sp2) intermediate D through the elimination of HBr. Finally, reductive elimination of D furnishes 4b-alkyl-10-

phenyl-4b,5-dihydroindeno[2,1-a]indenes 3 via the regeneration of Pd0 catalyst and thus completes the catalytic cycle.

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CONCLUSIONS In summary, we have disclosed an efficient domino palladiumcatalyzed cyclization for the synthesis of 4b-alkyl-10-phenyl4b,5-dihydroindeno[2,1-a]indenes. This process enabled the effective construction of three new C−C bonds, thus illustrates the power of transition-metal catalysis. Further extension of this domino process for the synthesis of polycyclic compounds is in progress.

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EXPERIMENTAL SECTION

General. Infrared analysis was recorded on FT-IR spectrophotometer. 1H NMR data was recorded on a 400 MHz spectrometer at 295 K in CDCl3; chemical shifts (δ ppm) and coupling constants (Hz) are reported in standard fashion with reference to either internal standard tetramethylsilane (TMS) (δH = 0.00 ppm) or CHCl3 (δH = 7.25 ppm). 13C NMR data was recorded on a 100 MHz spectrometer at RT in CDCl3; chemical shifts (δ ppm) are reported relative to CHCl3 [δC = 77.00 ppm (central line of triplet)]. In the 13C NMR, the nature of carbons (C, CH, CH2, and CH3) was determined by recording the DEPT-135 data and is given in parentheses and noted as s = singlet (for C), d = doublet (for CH), t = triplet (for CH2), and q = quartet (for CH3). In the 1H NMR, the following abbreviations were used throughout: s = singlet, d = doublet, t = triplet, q = quartet, qui = quintet, sept = septet, dd = doublet of doublet, m = multiplet, and br. s = broad singlet. The assignment of signals was confirmed by 1H, 13C 4256


Article

The Journal of Organic Chemistry Table 3. Synthesis of 4b-Methyl-10-phenyl-4b,5dihydroindeno[2,1-a]indenes 3a,b,c

Table 4. Synthesis of 4b-Methyl-10-phenyl-4b,5dihydroindeno[2,1-a]indenes 3a,b,c

a

Reaction conditions: 1-bromo-2-isopropenylbenzenes 1a and 1e (0.25 mmol), diaryl acetylenes 2g and 2i (0.62 mmol), Pd(OAc)2 (5 mol %), BINAP (10 mol %), TEBAC (1 equiv), K2CO3 (4 equiv), toluene (0.5 mL), 140 °C, 36−48 h. bYields in the parentheses are isolated yields of chromatographically pure products. cThe first alphabet of products 3ag + 3ag′ and 3ai, 3ei refers to the 1-bromo2-isopropenylbenzenes, while the second letter indicates the alkynes. CPD, and DEPT data. High-resolution mass values (HR-MS) were recorded on Q-TOF electron spray ionization (ESI) mode and atmospheric pressure chemical ionization (APCI) modes. All small scale dry reactions were carried out using Schleck tubes under nitrogen inert atmosphere. Reactions were monitored by TLC on silica gel using a combination of hexane and ethyl acetate as eluents. Reactions were generally run under argon or a nitrogen atmosphere. Solvents were distilled prior to use; petroleum ether with a boiling range of 60 to 80 °C was used. Palladium acetate, BINAP and TEBAC were purchased from Sigma-Aldrich and used as received. K2CO3 was purchased from Sigma-Aldrich and dried prior to use. Acme’s silica gel (60−120 mesh) was used for column chromatography (approximately 20 g per one gram of crude material). The starting materials, styrenes 1a−f and 1h−j, are known in the literature,1 and 1g was synthesized from 4a. (See the Supporting Information.) Biaryl acetylenes 2a−k are known in the literature.3 1-(Benzyloxy)-4-bromo-2-methoxy-5-(prop-1-en-2-yl)benzene (1g). An oven-dried RBF was equipped with a magnetic stir bar and 1(5-(benzyloxy)-2-bromo-4-methoxyphenyl)ethanone (1 equiv), Ph3pCH2 (2 equiv), and tbuoK (2 equiv) were added, under nitrogen inert atmosphere, and THF (15 mL) was added via syringe. And allowed the reaction mixture to stir at 0 °C to room temperature for 3 h. Progress of the reaction was monitored by TLC until the reaction is completed. Then, the reaction mixture was quenched by the addition of aqueous NaHCO3 solution and extracted with ethyl dichloromethane (3 × 20 mL). The organic layers were washed with saturated NaCl solution, dried (Na2SO4), and filtered. Evaporation of the solvent(s) under reduced pressure and purified on silica gel column chromatography (petroleum ether/ethyl acetate 100:0 to 99:01) gave the styrene 1g (95%) as liquid [TLC control (petroleum ether/ethyl acetate 100:0), Rf(2c) = 0.9, Rf(3ha) = 0.8, UV detection]. IR (MIR-ATR, 4000−600 cm−1): νmax = 2824, 1683, 1617, 1501, 1462, 1312, 1261, 1249, 1035, 827, 725 cm−1. 1H NMR (CDCl3, 400 MHz): δ = 7.45−7.25 (m, 5H, Ar−H), 7.03 (s, 1H, Ar−H), 6.74 (s, 1H, Ar− H), 5.17 (s, 1H, CHaHb), 5.10 (s, 2H, Ar−O−CH2), 4.80 (s, 1H, CHaHb), 3.80 (s, 3H, Ar-OCH3), 2.03 (s, 3H, CH3) ppm. 13C NMR

a

Reaction conditions: 1-bromo-2-isopropenylbenzenes 1e-h (0.25 mmol), diaryl acetylenes 2a-j (0.62 mmol), Pd(OAc)2 (5 mol %), BINAP (10 mol %), TEBAC (1 equiv), K2CO3 (4 equiv), toluene (0.5 mL), 140 °C, 36−48 h. bYields in the parentheses are isolated yields of chromatographically pure products. cThe first alphabet of products 3ea-ha refers to the 1-bromo-2-isopropenylbenzenes, while the second letter indicates the alkynes.

Scheme 1. Plausible Reaction Mechanism for the Formation of 3

(CDCl3, 100 MHz): δ = 149.1 (s, Ar−C), 147.1 (s, Ar−C), 145.4 (s, Ar−C), 136.7 (s, Ar−C), 128.6 (d, 2C, 2 × Ar−CH), 128.5 (s, Ar−C), 128.0 (d, 2C, 2 × Ar−CH), 128.5 (s, Ar−C), 127.9 (s, Ar−C), 127.4 (s, Ar−C), 116.2 (d, Ar−CH), 116.1 (t, Ar−O−CH2), 71.3 (d, CH2) 4257


Article

The Journal of Organic Chemistry and 56.3 (q, Ar-OCH3), 23.6 (q, CH3) ppm. HR-MS (APCI+) m/z calculated for [C17H17BrO2]+ = [M + H]+: 332.0412; found 332.0404. GP-1 (General Procedure for Indenes). A hot oven-dried screwcap vial was equipped with a magnetic stir bar, and Pd(OAc)2 (2.8 mg, 5 mol %), BINAP (15.3 mg, 10 mol %), TEBAC (56.7 mg, 0.25 mmol), and K2CO3 (138.6 mg, 1 mmol) were added, under nitrogen inert atmosphere, and toluene (0.3 mL) was added via syringe. After the addition of solvent the solution was heated at 140 °C for 10 min for pre catalyst formation and then brought to ambient temperature. A second oven-dried vial was equipped with the starting materials styrenes 1 (49.2−83.2 mg, 0.25 mmol), biaryl acetylenes 2 (111.2−196.2 mg, 0.62 mmol), and toluene (0.2 mL) at RT under nitrogen inert atmosphere, and then this solution was transferred to the first vial in which active catalyst is there via syringe. The reaction mixture was stirred at 140 °C for 36−48 h. Progress of the reaction was monitored by TLC until the reaction is completed. Then, the reaction mixture was cooled to room temperature, quenched by the addition of aqueous NaHCO3 solution, and extracted using ethyl acetate (3 × 20 mL). The organic layers were washed with saturated NaCl solution, dried (with Na2SO4), and filtered. Evaporation of the solvent(s) under reduced pressure and refinement of the crude mixture by silica gel column chromatography (petroleum ether/ethyl acetate) gave the indenes 3 (40−73%) as semisolid/solid. 4b-Methyl-10-(4-methylphenyl)-4b,5-dihydroindeno[2,1-a]indene (3aa). GP was carried out with 1-bromo-2-(prop-1-en-2yl)benzene 1a (49.2 mg, 0.25 mmol), 1,2-diphenylethyne 2a (111.2 mg, 0.62 mmol), palladium acetate (2.8 mg, 5 mol %), BINAP (15.3 mg, 10 mol %), TEBAC (56.7 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol), and toluene (0.5 mL). Refinement of the crude material by silica gel column chromatography (petroleum ether/ethyl acetate, 100:0 to 99:1) gave the indene 3aa (49.9 mg, 68%) as a light yellow jelly compound [TLC control (petroleum ether/ethyl acetate 100:0), Rf(2c) = 0.9, Rf(3aa) = 0.8, UV detection]. IR (MIR-ATR, 4000−600 cm−1): νmax = 3025, 2953, 2910, 2859, 2171, 2138, 1984, 1701, 1658, 1605, 1521, 1452, 1371, 1268, 1248, 1042, 824, 737 cm−1. 1H NMR (CDCl3, 400 MHz): δ = 7.62 (d, 2H, J = 6.8 Hz, Ar−H), 7.52 (d, 1H, J = 6.8 Hz, Ar−H), 7.50−7.43 (m, 3H, Ar−H), 7.40−7.36 (m, 2H, Ar−H), 7.30−7.19 (m, 3H, Ar−H), 7.16−7.07 (m, 2H, Ar−H), 3.05− 3.01 (d, 1H, J = 14.7 Hz, CHaHb), 2.84−2.80 (d, 1H, J = 14.7 Hz, CHaHb), 1.44 (s, 3H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 158.7 (s, Ar−C), 151.4 (s, Ar−C), 151.2 (s, Ar−C), 146.6 (s, Ar−C), 135.6 (s, Ar−C), 134.8 (s, Ar−C), 133.1 (s, Ar−C), 129.3 (d, 2C, 2 × Ar−CH), 128.3 (d, 2C, 2 × Ar−CH), 127.6 (d, Ar−CH), 127.4 (d, Ar−CH), 126.9 (d, Ar−CH), 126.7 (d, Ar−CH), 126.0 (d, Ar−CH), 125.0 (d, Ar−CH), 122.8 (d, Ar−CH), 122.7 (d, Ar−CH), 121.3 (d, Ar−CH), 61.8 [s, C(CH3)CH2Ar], 40.2 [t, C(CH3)CH2Ar], 27.1 (q, CH3) ppm. HR-MS (APCI+) m/z calculated for [C23H19]+ = [M + H]+: 295.1481; found 295.1477. 4b,7-Dimethyl-10-(p-tolyl)-4b,5-dihydroindeno[2,1-a]indene (3ab). GP was carried out with 1-bromo-2-(prop-1-en-2-yl)benzene 1a (49.2 mg, 0.25 mmol), 1,2-di-p-tolylethyne 2b (128.7 mg, 0.625 mmol), palladium acetate (2.8 mg, 5 mol %), BINAP (15.3 mg, 10 mol %), TEBAC (56.7 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol), followed by toluene (0.5 mL). Refinement of the crude material by silica gel column chromatography (petroleum ether/ethyl acetate, 100:0 to 99:1) gave the indene 3ab (49.1 mg, 61%) as a light yellow jelly compound [TLC control (petroleum ether/ethyl acetate 100:0), Rf(2c) = 0.8, Rf(3aa) = 0.7, UV detection]. IR (MIR-ATR, 4000−600 cm−1): νmax = 3029, 2957, 2909, 2850, 2169, 2138, 1989, 1705, 1648, 1605, 1521, 1456, 1379, 1263, 1248, 1047, 824, 739 cm−1. 1H NMR (CDCl3, 400 MHz): δ = 7.49 (d, 1H, J = 7.8 Hz, Ar−H), 7.48 (d, 1H, J = 7.3 Hz, Ar−H), 7.42 (dd, 1H, J = 7.8 and 7.3 Hz, Ar−H), 7.40− 7.31 (m, 2H, Ar−H), 7.30−7.10 (m, 4H, Ar−H), 7.07 (d, 1H, J = 3.0 Hz, Ar−H), 6.95−6.80 (m, 1H, Ar−H), 2.94 (dd, 1H, J = 14.2 and 4.9 Hz, CHaHb), 2.75 (dd, 1H, J = 14.2 and 4.4 Hz, CHaHb), 2.37 (s, 3H, ArCH3), 2.27 (s, 3H, ArCH3), 1.39 (d, 3H, J = 4.9 Hz, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 158.4 (s, Ar−C), 151.4 (s, Ar−C), 151.3 (s, Ar−C), 146.8 (s, Ar−C), 137.3 (s, Ar−C), 137.1 (s, Ar−C), 133.0 (s, Ar−C), 132.1 (s, Ar−C), 132.0 (s, Ar−C), 129.1 (d, 2C, 2 × Ar−CH), 129.0 (d, 2C, 2 × Ar−CH), 127.4 (d, Ar−CH), 126.8 (d,

Ar−CH), 126.7 (d, Ar−CH), 124.7 (d, Ar−CH), 122.7 (d, Ar−CH), 122.4 (d, Ar−CH), 121.1 (d, Ar−CH), 61.8 [s, C(CH3)CH2Ar], 40.1 [t, C(CH3)CH2Ar], 27.2 (q, CH3), 21.5 (q, ArCH3), 21.4 (q, ArCH3) ppm. HR-MS (APCI+) m/z calculated for [C25H23]+ = [M + H]+: 323.1794; found 323.1776. 4b,8-Dimethyl-10-(m-tolyl)-4b,5-dihydroindeno[2,1-a]indene (3ac). GP was carried out with 1-bromo-2-(prop-1-en-2-yl)benzene 1a (49.2 mg, 0.25 mmol), 1,2-di-m-tolylethyne 2c (128.7 mg, 0.625 mmol), palladium acetate (2.8 mg, 5 mol %), BINAP (15.3 mg, 10 mol %), TEBAC (56.7 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol), followed by toluene (0.5 mL). Refinement of the crude material by silica gel column chromatography (petroleum ether/ethyl acetate, 100:0 to 99:1) gave the indene 3ac (49.9 mg, 62%) as a light yellow jelly compound, recrystallized the solid with dichloromethane/hexane, mp 129−130 °C. [TLC control (petroleum ether/ethyl acetate 100:0), Rf(2c) = 0.8, Rf(3ac) = 0.7, UV detection]. IR (MIR-ATR, 4000−600 cm−1): νmax = 3029, 2953, 2919, 2861, 2171, 2141, 1989, 1707, 1661, 1608, 1521, 1455, 1379, 1270, 1240, 1049, 828, 745 cm−1. 1H NMR (CDCl3, 400 MHz): δ = 7.45−7.35 (m, 6H, Ar−H), 7.28−7.17 (m, 4H, Ar−H), 6.97 (d, 1H, J = 7.34 Hz, Ar−H), 3.01−2.97 (d, 1H, J = 14.67 Hz,, CHaHb), 2.98 (d, 1H, J = 14.67, CHaHb), 2.44 (s, 3H, ArCH3), 2.27 (s, 3H, ArCH3), 1.42 (s, 3H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 158.7 (s, Ar−C), 151.4 (s, Ar−C), 148.3 (s, Ar−C), 146.7 (s, Ar−C), 137.8 (s, Ar−C), 136.2 (s, Ar−C), 135.7 (s, Ar−C), 134.8 (s, Ar−C), 132.9 (s, Ar−C), 129.9 (d, Ar−CH), 128.4 (d, Ar−CH), 128.3 (d, Ar−CH), 128.2 (d, Ar−CH), 126.8 (d, Ar− CH), 126.5 (d, Ar−CH), 125.7 (d, Ar−CH), 124.8 (d, Ar−CH), 123.4 (d, Ar−CH), 122.7 (d, Ar−CH), 121.3 (d, Ar−CH), 62.0 [s, C(CH3)CH2Ar], 39.9 [t, C(CH3)CH2Ar], 27.2 (q, CH3), 21.5 (q, ArCH3), 21.5 (q, ArCH3) ppm. HR-MS (APCI+) m/z calculated for [C25H23]+ = [M + H]+: 323.1794; found 323.1780. 7-Methoxy-10-(4-methoxyphenyl)-4b-methyl-4b,5dihydroindeno[2,1-a]indene (3ad). GP was carried out with 1bromo-2-(prop-1-en-2-yl)benzene 1a (49.2 mg, 0.25 mmol), 1,2-bis(4methoxyphenyl)ethyne 2d (148.7 mg, 0.625 mmol), palladium acetate (2.8 mg, 5 mol %), BINAP (15.3 mg, 10 mol %), TEBAC (56.7 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol), followed by toluene (0.5 mL). Refinement of the crude material by silica gel column chromatography (petroleum ether/ethyl acetate, 96:4 to 97:3) gave the indene 3ad (53.1 mg, 60%) as a light yellow jelly compound [TLC control (petroleum ether/ethyl acetate 95:5), Rf(2c) = 0.6, Rf(3ad) = 0.5, UV detection]. IR (MIR-ATR, 4000−600 cm−1): νmax = 3030, 2959, 2911, 2858, 2175, 2139, 1980, 1707, 1652, 1607, 1529, 1457, 1370, 1264, 1241, 1048, 825, 730 cm−1. 1H NMR (CDCl3, 400 MHz): δ = 7.55 (d, 2H, J = 8.8 Hz, Ar−H), 7.46 (d, 1H, J = 8.3 Hz, Ar−H), 7.41 (d, 1H, J = 7.3 Hz, Ar−H), 7.38 (d, 1H, J = 7.8 Hz Ar−H), 7.28− 7.24 (t, 1H, J = 6.8 Hz, Ar−H), 7.20−7.17 (t, 1H, J = 8.3 Hz, Ar−H), 7.03 (s, 1H, Ar−H), 7.01 (s, 1H, Ar−H), 6.87 (s, 1H, Ar−H), 6.88− 6.65 (dd, 1H, J = 8.3 and J = 2.4 Hz, Ar−H), 3.88 (s, 3H, ArOCH3), 3.79 (s, 3H, ArOCH3), 3.01−2.98 (d, 1H, J = 14.7 Hz, CHaHb), 2.83− 2.79 (d, 1H, J = 14.7 Hz, CHaHb), 1.42 (s, 3H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 159.5 (s, Ar−C), 158.9 (s, Ar−C), 157.7 (s, Ar−C), 153.2 (s, Ar−C), 151.2 (s, Ar−C), 147.1 (s, Ar−C), 130.7 (s, Ar−C), 130.4 (d, 2C, 2 × Ar−CH), 128.7 (s, Ar−C), 127.5 (s, Ar−C), 126.8 (d, Ar−CH), 124.5 (d, Ar−CH), 123.2 (d, Ar−CH), 122.7 (d, Ar−CH), 120.9 (d, Ar−CH), 113.7 (d, 2C, 2 × Ar−CH), 112.3 (d, Ar−CH), 112.0 (d, Ar−CH), 61.9 [s, C(CH3)CH2Ar], 55.4 (q, 3H, ArOCH3), 55.3 (q, 3H, ArOCH3), 40.4 [t, C(CH3)CH2Ar], 27.5 (q, CH3) ppm. HR-MS (APCI+) m/z calculated for [C25H23O2]+ = [M + H]+: 355.1693; found 355.1685. 8-Methoxy-10-(3-methoxyphenyl)-4b-methyl-4b,5dihydroindeno[2,1-a]indene(3ae). GP was carried out with 1-bromo2-(prop-1-en-2-yl)benzene 1a (49.2 mg, 0.25 mmol), 1,2-bis(3methoxyphenyl)ethyne 2e (148.7 mg, 0.625 mmol), palladium acetate (2.8 mg, 5 mol %), BINAP (15.3 mg, 10 mol %), TEBAC (56.7 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol), followed by toluene (0.5 mL). Refinement of the crude material by silica gel column chromatography (petroleum ether/ethyl acetate, 96:4 to 97:3) gave the indene 3ae (52.2 mg, 59%) as a light yellow jelly compound [TLC control (petroleum ether/ethyl acetate 95:5), Rf(2c) = 0.6, Rf(3ae) = 4258


Article

The Journal of Organic Chemistry 0.5, UV detection]. IR (MIR-ATR, 4000−600 cm−1): νmax = 3027, 2950, 2917, 2855, 2178, 2139, 1983, 1705, 1660, 1605, 1529, 1454, 1371, 1269, 1248, 1045, 834, 735 cm−1. 1H NMR (CDCl3, 400 MHz): δ = 7.45−7.39 (q, 3H, J = 7.8 Hz, Ar−H), 7.30−7.19 (m, 4H, Ar−H), 7.16 (dd, 1H, J = 2.45 Hz, Ar−H), 7.14 (d, 1H, J = 2.4 Hz Ar−H), 6.96−6.93 (dd, 1H, J = 8.3 and 2.9 Hz, Ar−H), 6.74−6.72 (dd, 1H, J = 8.3 and 2.9 Hz, Ar−H), 3.85 (s, 3H, ArOCH3), 3.73 (s, 3H, ArOCH3), 3.00−2.96 (d, 1H, J = 14.2 Hz, CHaHb), 2.78−2.75 (d, 1H, J = 14.2 Hz, CHaHb), 1.44 (s, 3H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 159.5 (s, Ar−C), 158.9 (s, Ar−C), 158.7 (s, Ar−C), 158.6 (s, Ar− C), 151.4 (s, Ar−C), 146.4 (s, Ar−C), 143.3 (s, Ar−C), 136.6 (s, Ar− CH), 136.1 (s, Ar−C), 133.0 (s, Ar−C), 129.3 (d, Ar−CH), 126.9 (d, Ar−CH), 126.4 (d, Ar−CH), 125.0 (d, Ar−CH), 122.8 (d, Ar−CH), 121.9 (s, Ar−C), 121.4 (d, Ar−CH), 114.3 (d, Ar−CH), 113.6 (d, Ar−CH), 113.2 (d, Ar−CH), 108.3 (d, Ar−CH), 62.3 [s, C(CH3)CH2Ar], 55.3 (2 × q, 6H, 2 × ArOCH3), 39.4 [t, C(CH3)CH2Ar], 27.2 (q, CH3) ppm. HR-MS (APCI+) m/z calculated for [C25H23O2]+ = [M + H]+: 355.1693; found 355.1692. 7-Fluoro-10-(4-fluorophenyl)-4b-methyl-4b,5-dihydroindeno[2,1a]indene (3af). GP was carried out with 1-bromo-2-(prop-1-en-2yl)benzene 1a (49.2 mg, 0.25 mmol), 1,2-bis(4-fluorophenyl)ethyne 2f (133.7 mg, 0.625 mmol), palladium acetate (2.8 mg, 5 mol %), BINAP (15.3 mg, 10 mol %), TEBAC (56.7 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol), followed by toluene (0.5 mL). Refinement of the crude material by silica gel column chromatography (petroleum ether/ethyl acetate, 100:0 to 99:1) gave the indene 3af (45.3 mg, 55%) as a light yellow jelly compound [TLC control (petroleum ether/ethyl acetate 100:0), Rf(2c) = 0.8, Rf(3af) = 0.7, UV detection]. IR (MIR-ATR, 4000−600 cm−1): νmax = 2924, 2853, 1734, 1683, 1607, 1501, 1461, 1371, 1268, 1148, 1043, 829, 801, 730 cm−1. 1H NMR (CDCl3, 400 MHz): δ = 7.57−7.53 (m, 2H, Ar−H), 7.43−7.38 (m, 2H, Ar−H), 7.32 (d, 1H, J = 7.3 Hz, Ar−H), 7.29−7.25 (dt, 1H, J = 6.3 Hz, Ar− H), 7.23−7.15 (m, 3H, Ar−H), 7.02−6.99 (dd, 1H, J = 8.3 Hz Ar−H), 3.03−3.00 (d, 1H, J = 14.7 Hz, CHaHb), 2.82−2.79 (d, 1H, J = 14.7 Hz, CHaHb), 1.41 (s, 3H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 163.8 (s, Ar−C, Jc‑f = 247.2), 163.5 (s, Ar−C, Jc‑f = 246.5), 157.4 (s, Ar−C), 153.7 (s, Ar−C), 153.6 (s, Ar−C), 151.1 (s, Ar−C), 146.5 (s, Ar−C), 131.6 (t, Ar−C), 130.9 (d, Ar−CH), 130.8 (d, Ar−CH), 130.6 (s, Ar−C), 127.1 (d, Ar−CH), 125.2 (d, Ar−CH), 123.4 (d, Ar−CH), 123.3 (d, Ar−CH), 122.9 (d, Ar−CH), 121.1 (d, Ar−CH), 115.6 (d, 2C, 2 × Ar−CH), 113.9 (d, 2C, 2 × Ar−CH), 113.7 (d, 2C, 2 × Ar− CH), 62.3 [s, C(CH3)CH2Ar], 40.4 [t, C(CH3)CH2Ar], 27.1 (q, CH3) ppm. HR-MS (APCI+) m/z calculated for [C23H16F2]+ = [M]+: 330.1215; found 330.1207. 10-(4-Fluorophenyl)-4b-methyl-4b,5-dihydroindeno[2,1-a]indene and 7-fluoro-4b-methyl-10-phenyl-4b,5-dihydroindeno[2,1-a]indene (3ag). GP was carried out with 1-bromo-2-(prop-1-en-2yl)benzene 1a (49.2 mg, 0.25 mmol), 1-fluoro-3-(phenylethynyl)benzene 2g (122.5 mg, 0.625 mmol), palladium acetate (2.8 mg, 5 mol %), BINAP (15.3 mg, 10 mol %), TEBAC (56.7 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol), followed by toluene (0.5 mL). Refinement of the crude material by silica gel column chromatography (petroleum ether/ethyl acetate, 100:0 to 99:1) gave the indene 3ag (45.3 mg, 55%) as a light yellow jelly compound [TLC control (petroleum ether/ethyl acetate 100:0), Rf(2c) = 0.8, Rf(3ag) = 0.7, UV detection]. IR (MIR-ATR, 4000−600 cm−1): νmax = 3010, 2958, 2911, 2850, 2172, 2138, 1984, 1701, 1658, 1605, 1521, 1452, 1371, 1268, 1248, 1043, 828, 740 cm−1. 1H NMR (CDCl3, 400 MHz): δ = 7.61− 7.56 (m, 3H, Ar−H), 7.50−7.45 (m, 4H, Ar−H), 7.43−7.36 (m, 3H, Ar−H), 7.34−7.25 (m, 4H, Ar−H), 7.23−7.09 (m, 6H, Ar−H), 7.00 (d, 1H, J = 8.3 Hz, Ar−H), 6.79 (t, 1H, J = 9.3 and 8.3 Hz, Ar−H), 3.05−2.99 (q, 2H, J = 8.8 Hz, CHaHb), 2.83−2.76 (t, 2H, J = 14.2 Hz, CHaHb), 1.43 (s, 6H, 2 × CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 163.7 (s, Ar−C, Jc‑f = 247.2), 163.5 (s, Ar−C, Jc‑f = 245.2), 158.8 (s, Ar−C), 157.3 (s, Ar−C), 153.6 (s, Ar−C), 153.5 (s, Ar−C), 151.3 (s, Ar−C), 151.1 (s, Ar−C), 146.5 (s, Ar−C), 135.4 (s, Ar−C), 134.6 (s, Ar−C), 132.7 (s, Ar−C), 132.0 (s, Ar−C), 131.7 (s, Ar−C), 130.9 (d, Ar−CH), 130.8 (s, 2C, Ar−C), 129.2 (d, 2C, 2 × Ar−CH), 128.4 (d, 2C, 2 × Ar−CH), 127.7 (d, Ar−CH), 127.5 (d, Ar−CH), 127.0 (d, Ar−CH), 126.9 (d, Ar−CH), 126.7 (d, Ar−CH), 126.1 (d, Ar−CH),

125.0 (2 × d, 2 × Ar−CH), 123.5 (d, Ar−CH), 123.4 (d, Ar−CH), 122.8 (d, Ar−CH), 122.7 (d, Ar−CH), 122.5 (d, Ar−CH), 121.3 (d, Ar−CH), 121.0 (d, Ar−CH), 115.4 (d, Ar−CH), 115.2 (d, Ar−CH), 113.8 (2 × d, 2 × Ar−CH), 113.6 (2 × d, 2 × Ar−CH), 62.2 [s, C(CH3)CH2Ar], 61.8 [s, C(CH3)CH2Ar], 40.3 [t, C(CH3)CH2Ar], 40.2 [t, C(CH3)CH2Ar], 27.1 (q, CH3), 27.0 (q, CH3) ppm. HR-MS (APCI+) m/z calculated for [C23H18F]+ = [M + H]+: 313.1387; found 313.1381. 4a-Methyl-9-(thiophen-2-yl)-4,4a-dihydrobenzo[4,5]pentaleno[1,2-b]thiophene (3ah). GP was carried out with 1-bromo-2-(prop-1en-2-yl)benzene 1a (49.2 mg, 0.25 mmol), 1,2-di(thiophen-2-yl)ethyne 2h (118.5 mg, 0.625 mmol), palladium acetate (2.8 mg, 5 mol %), BINAP (15.3 mg, 10 mol %), TEBAC (56.7 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol), followed by toluene (0.5 mL). Refinement of the crude material by silica gel column chromatography (petroleum ether/ethyl acetate, 100:0 to 99:1) gave the indene 3ah (45.9 mg, 60%) as a light yellow jelly compound [TLC control (petroleum ether/ethyl acetate 100:0), Rf(2c) = 0.8, Rf(3ah) = 0.7, UV detection]. IR (MIR-ATR, 4000−600 cm−1): νmax = 2924, 2910, 2855, 2171, 2138, 1980, 170, 1658, 1605, 1521, 1452, 1371, 1268, 1248, 1042, 824, 740 cm−1. 1H NMR (CDCl3, 400 MHz): δ = 7.77 (d, 1H, J = 7.8 Hz, Ar−H), 7.46 (dd, 1H, J = 2.9 and 0.1 Hz, Ar−H), 7.39−7.31 (m, 3H, Ar−H), 7.24−7.20 (m, 3H, Ar−H), 7.01 (d, 1H, J = 4.9 Hz, Ar−H), 3.00−2.96 (d, 1H, J = 14.2 Hz, CHaHb), 2.85−2.82 (d, 1H, J = 14.2 Hz, CHaHb), 1.56 (s, 3H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 157.2 (s, Ar−C), 154.0 (s, Ar−C), 150.8 (s, Ar−C), 144.9 (s, Ar−C), 136.9 (s, Ar−C), 135.7 (s, Ar−C), 127.9 (d, Ar−CH), 127.4 (d, Ar−CH), 127.0 (d, Ar−CH), 125.6 (d, Ar−CH), 125.0 (d, Ar−CH), 124.3 (d, Ar−CH), 124.2 (d, Ar−CH), 122.4 (d, Ar−CH), 121.9 (s, Ar−C), 121.5 (d, Ar−CH), 67.5 [s, C(CH3)CH2Ar], 37.6 [t, C(CH3)CH2Ar], 29.9 (q, CH3) ppm. HR-MS (APCI+) m/z calculated for [C19H15S2]+ = [M + H]+: 307.0610; found 307.0605. Methyl 9b-Methyl-5-phenyl-9b,10-dihydroindeno[2,1-a]indene2-carboxylate (3ai). GP was carried out with 1-bromo-2-(prop-1en-2-yl)benzene 1a (49.2 mg, 0.25 mmol), methyl 4-(phenylethynyl)benzoate 2i (147.5 mg, 0.625 mmol), palladium acetate (2.8 mg, 5 mol %), BINAP (15.3 mg, 10 mol %), TEBAC (56.7 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol), followed by toluene (0.5 mL). Refinement of the crude material by silica gel column chromatography (petroleum ether/ethyl acetate, 92:8 to 93:7) gave the indene 3ai (45.4 mg, 52%) as a light yellow jelly compound [TLC control (petroleum ether/ethyl acetate 91:9), Rf(2c) = 0.6, Rf(3ai) = 0.5, UV detection]. IR (MIR-ATR, 4000−600 cm−1): νmax = 2953, 2910, 2859, 2171, 2138, 1984, 1735, 1701, 1658, 1605, 1521, 1371, 1268, 1248, 1042, 824, 737 cm−1. 1H NMR (CDCl3, 400 MHz): δ = 7.95 (s, 1H, Ar−H), 7.80 (d, 1H, J = 7.8 Hz, Ar−H), 7.61 (d, 2H, J = 7.3 Hz, Ar− H), 7.55−7.40 (m, 6H, Ar−H), 7.28 (d, 2H, J = 7.8 Hz, Ar−H), 3.89 (s, 3H, Ar−COOMe), 3.11−3.07 (d, 1H, J = 14.7 Hz, CHaHb), 2.86− 2.82 (d, 1H, J = 14.7 Hz, CHaHb), 1.43 (s, 3H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 167.2 (s, Ar−C), 157.3 (s, Ar−C), 151.5 (s, Ar−C), 151.2 (s, Ar−C), 146.2 (s, Ar−C), 140.2 (s, Ar−C), 135.6 (s, Ar−C), 134.3 (s, Ar−C), 129.3 (d, 2C, 2 × Ar−CH), 128.8 (d, 2C, 2 × Ar−CH), 128.6 (d, Ar−CH), 128.5 (d, Ar−CH), 128.1 (d, Ar− CH), 127.1 (d, Ar−CH), 126.9 (d, Ar−CH), 125.7 (d, Ar−CH), 123.0 (d, Ar−CH), 122.2 (d, Ar−CH), 121.9 (d, Ar−CH), 62.1 [s, C(CH3)CH2Ar], 52.1 (q, ArCOOCH3), 40.2 [t, C(CH3)CH2Ar], 26.8 (q, CH3) ppm. HR-MS (APCI+) m/z calculated for [C25H20O2]+ = [M + H]+: 352.4251; found 352.4249. 10-(3,4-Dimethoxyphenyl)-7,8-dimethoxy-4b-methyl-4b,5dihydroindeno[2,1-a]indene (3aj). GP was carried out with 1-bromo2-(prop-1-en-2-yl)benzene 1a (49.2 mg, 0.25 mmol), 1,2-bis(4methoxyphenyl)ethyne 2j (186 mg, 0.625 mmol), palladium acetate (2.8 mg, 5 mol %), BINAP (15.3 mg, 10 mol %), TEBAC (56.7 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol), followed by toluene (0.5 mL). Refinement of the crude material by silica gel column chromatography (petroleum ether/ethyl acetate, 60:40 to 70:30) gave the indene 3aj (56.9 mg, 55%) as a light yellow jelly compound [TLC control (petroleum ether/ethyl acetate 60:40), Rf(2c) = 0.7, Rf(3aj) = 0.5, UV detection]. IR (MIR-ATR, 4000−600 cm−1): νmax = 2924, 2854, 1735, 1683, 1607, 1500, 1466, 1371, 1268, 1248, 1042, 4259


Article

The Journal of Organic Chemistry 824, 805,737 cm−1. 1H NMR (CDCl3, 400 MHz): δ = 7.42−7.38 (t, 2H, J = 8.8 and 8.3 Hz, Ar−H), 7.28−7.24 (m, 2H, Ar−H), 7.21−7.14 (m, 3H, Ar−H), 7.11 (s, 1H, Ar−H), 6.99 (d, 1H, J = 8.3 Hz, Ar−H), 6.87 (s, 1H, Ar−H), 3.95 (s, 3H, ArOCH3), 3.91 (s, 3H, ArOCH3), 3.88 (s, 3H, ArOCH3), 3.77 (s, 3H, ArOCH3), 2.98−2.94 (d, 1H, J = 14.2 Hz, CHaHb), 2.82−2.78 (d, 1H, J = 14.2 Hz, CHaHb), 1.44 (s, 3H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 158.5 (s, Ar−C), 151.1 (s, Ar−C), 149.0 (s, Ar−C), 148.7 (s, Ar−C), 148.4 (s, Ar−C), 147.9 (s, Ar−C), 147.0 (s, Ar−C), 144.1 (d, Ar−CH), 130.3 (s, Ar− C), 128.1 (s, Ar−C), 127.8 (s, Ar−C), 126.9 (d, Ar−CH), 124.5 (d, Ar−CH), 122.6 (d, Ar−CH), 121.7 (d, Ar−CH), 120.9 (d, Ar−CH), 112.1 (d, Ar−CH), 110.9 (d, Ar−CH), 109.4 (d, Ar−CH), 105.0 (d, Ar−CH), 62.1 [s, C(CH3)CH2Ar], 56.0 (2 × q, 6H, 2 × ArOCH3), 55.9 (q, 3H, ArOCH3), 55.9 (q, 3H, ArOCH3), 40.0 [t, C(CH3) CH2Ar], 27.9 (q, CH3) ppm. HR-MS (APCI+) m/z calculated for [C27H27O4]+ = [M + H]+: 416.1938; found 416.1932. 4b-Ethyl-10-phenyl-4b,5-dihydroindeno[2,1-a]indene (3ba). GP was carried out with 1-bromo-2-(but-1-en-2-yl)benzene 1b (49.2 mg, 0.25 mmol), 1,2-diphenylethyne 2a (111.2 mg, 0.625 mmol), palladium acetate (2.8 mg, 5 mol %), BINAP (15.3 mg, 10 mol %), TEBAC (56.7 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol), followed by toluene (0.5 mL). Refinement of the crude material by silica gel column chromatography (petroleum ether/ethyl acetate, 100:0 to 99:01) gave the indene 3ba (44.6 mg, 58%) as a light yellow jelly compound, [TLC control (petroleum ether/ethyl acetate 100:0), Rf(2c) = 0.8, Rf(3ba) = 0.7, UV detection]. IR (MIR-ATR, 4000−600 cm−1): νmax = 2925, 2859, 1738, 1684, 1607, 1501, 1461, 1371, 1397, 1268, 1245, 1043, 824, 808, 747 cm−1. 1H NMR (CDCl3, 400 MHz): δ = 7.64−7.61 (dd, 2H, J = 6.8 and 1.5 Hz, Ar−H), 7.54−7.47 (m, 3H, Ar−H), 7.41−7.37 (m, 3H, Ar−H), 7.30−7.25 (m, 2H, Ar−H), 7.23− 7.19 (m, 1H, Ar−H), 7.16−7.07 (m, 2H, Ar−H), 3.09−3.06 (d, 1H, J = 14.7 Hz, CHaHb), 2.87−2.84 (d, 1H, J = 14.7 Hz, CHaHb), 2.07− 1.74 (q, 2H, J = 7.3 Hz, CH2-CH3), 0.56 (t, 3H, J = 7.3 Hz, CH2− CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 156.8 (s, Ar−C), 151.6 (s, Ar−C), 149.5 (s, Ar−C), 147.9 (s, Ar−C), 135.9 (s, Ar−C), 134.9 (s, Ar−C), 134.4 (s, Ar−C), 129.3 (d, 2C, 2 × Ar−CH), 128.3 (d, 2C, 2 × Ar−CH), 127.6 (d, Ar−CH), 127.3 (d, Ar−CH), 126.8 (s, Ar− C), 126.6 (d, Ar−CH), 125.9 (d, Ar−CH), 124.7 (d, Ar−CH), 122.9 (d, Ar−CH), 122.4 (d, Ar−CH), 120.9 (d, Ar−CH), 65.7 [s, C(CH2− CH3)CH2Ar], 39.6 [t, C(CH2−CH3)CH2Ar], 33.1 [t, C(CH2CH3)CH2Ar], 8.8 (q, CH2−CH3) ppm. HR-MS (APCI+) m/z calculated for [C24H21]+ = [M + H]+: 309.1638; found 309.1631. 4b-Ethyl-7-methyl-10-(p-tolyl)-4b,5-dihydroindeno[2,1-a]indene (3bb). GP was carried out with 1-bromo-2-(but-1-en-2-yl)benzene 1b (52.7 mg, 0.25 mmol), 1,2-di-p-tolylethyne 2b (128.7 mg, 0.625 mmol), palladium acetate (2.8 mg, 5 mol %), BINAP (15.3 mg, 10 mol %), TEBAC (56.7 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol), followed by toluene (0.5 mL). Refinement of the crude material by silica gel column chromatography (petroleum ether/ethyl acetate, 100:0 to 99:1) gave the indene 3bb (53.7 mg, 64%) as a light yellow jelly compound [TLC control (petroleum ether/ethyl acetate 100:0), Rf(2c) = 0.8, Rf(3bb) = 0.7, UV detection]. IR (MIR-ATR, 4000−600 cm−1): νmax = 3025, 2956, 2911, 2859, 2173, 2138, 1985, 1701, 1658, 1605, 1521, 1452, 1389, 1371, 1268, 1248, 1042, 828, 732 cm−1. 1H NMR (CDCl3, 400 MHz): δ = 7.52 (s, 1H, Ar−H), 7.50 (s, 1H, Ar− H), 7.42 (d, 1H, J = 7.8 Hz, Ar−H), 7.38−7.35 (m, 2H, Ar−H), 7.29− 7.23 (m, 3H, Ar−H), 7.19−7.16 (dt, 1H, J = 6.4 and 1.0 Hz, Ar−H), 7.11 (s, 1H, Ar−H), 6.90 (d, 1H, J = 7.3 Hz, Ar−H), 3.03−2.99 (d, 1H, J = 14.7 Hz, CHaHb), 2.83−2.79 (d, 1H, J = 14.7 Hz, CHaHb), 2.42 (s, 3H, ArCH3), 2.31 (s, 3H, ArCH3), 2.04−1.72 (m, 2H, CH2CH3), 0.55 (t, 3H, J = 7.3 Hz, CH2−CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 156.4 (s, Ar−C), 151.9 (s, Ar−C), 149.5 (s, Ar−C), 148.2 (s, Ar−C), 137.3 (s, Ar−C), 137.2 (s, Ar−C), 133.5 (s, Ar−C), 133.4 (s, Ar−C), 132.0 (s, Ar−C), 129.1 (d, 2C, 2 × Ar−CH), 129.0 (d, 2C, 2 × Ar−CH), 127.4 (d, Ar−CH), 126.8 (d, Ar−CH), 126.7 (s, Ar−C), 124.4 (d, Ar−CH), 122.8 (d, Ar−CH), 122.1 (d, Ar−CH), 120.8 (d, Ar−CH), 65.6 [s, C(CH2−CH3)CH2Ar], 39.4 [t, C(CH2− CH3)CH2Ar], 33.2 [t, C(CH2-CH3)CH2Ar], 21.5 (q, 3H, ArCH3), 21.4 (q, 3H, ArCH3), 8.8 (q, CH2−CH3) ppm. HR-MS (APCI+) m/z calculated for [C26H25]+ = [M + H]+: 337.1951; found 337.1945.

4b-Ethyl-7-fluoro-10-(4-fluorophenyl)-4b,5-dihydroindeno[2,1a]indene (3bf). GP was carried out with 1-bromo-2-(but-1-en-2yl)benzene 1a (52.7 mg, 0.25 mmol), 1,2-bis(4-fluorophenyl)ethyne 2f (133.7 mg, 0.625 mmol), palladium acetate (2.8 mg, 5 mol %), BINAP (15.3 mg, 10 mol %), TEBAC (56.7 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol), followed by toluene (0.5 mL). Refinement of the crude material by silica gel column chromatography (petroleum ether/ethyl acetate, 100:0 to 99:1) gave the indene 3bf (51.6 mg, 60%) as a light yellow jelly compound [TLC control (petroleum ether/ethyl acetate 100:0), Rf(2c) = 0.8, Rf(3bf) = 0.7, UV detection]. IR (MIR-ATR, 4000−600 cm−1): νmax = 2924, 2853, 1680, 1607, 1501, 1461, 1374, 1268, 1248, 1134, 1052, 826, 809, 730 cm−1. 1H NMR (CDCl3, 400 MHz): δ = 7.57−7.54 (m, 2H, Ar−H), 7.40−7.36 (m, 2H, Ar−H), 7.31−7.25 (m, 2H, Ar−H), 7.22−7.16 (m, 3H, Ar−H), 7.00 (d, 1H, J = 8.8 Hz, Ar−H), 6.82−6.77 (dt, 1H, J = 8.8 and 2.4 Hz Ar−H), 3.07−3.04 (d, 1H, J = 14.7 Hz, CHaHb), 2.86−2.82 (d, 1H, J = 14.7 Hz, CHaHb), 2.05−1.71 (m, 2H, CH2-CH3), 0.55 (t, 3H, J = 7.3 Hz, CH2−CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 163.7 (s, Ar−C, Jc‑f = 242.1 Hz), 163.5 (s, Ar−C, Jc‑f = 246.5 Hz), 155.5 (s, Ar−C), 154.1 (s, Ar−C), 154.0 (s, Ar−C), 149.2 (s, Ar−C), 147.8 (s, Ar−C), 132.9 (s, Ar−C), 131.9 (s, Ar−C), 130.8 (d, Ar−CH), 130.7 (d, Ar− CH), 127.0 (d, Ar−CH), 124.9 (d, Ar−CH), 123.1 (d, Ar−CH), 123.0 (d, Ar−CH), 122.9 (d, Ar−CH), 120.7 (d, Ar−CH), 115.5 (d, 2C, 2 × Ar−CH), 113.7 (d, 2C, 2 × Ar−CH), 113.5 (d, 2C, 2 × Ar− CH), 66.0 [s, C(CH2−CH3)CH2Ar], 39.6 [t, C(CH2−CH3)CH2Ar], 33.1 [t, C(CH2-CH3)CH2Ar], 8.8 (q, CH2−CH3) ppm. HR-MS (APCI+) m/z calculated for [C24H18F2]+ = [M]+: 344.1371; found 344.1375. 10-Phenyl-4b-propyl-4b,5-dihydroindeno[2,1-a]indene (3ca). GP was carried out with 1-bromo-2-(pent-1-en-2-yl)benzene 1c (56.2 mg, 0.25 mmol), 1,2-diphenylethyne 2a (111.2 mg, 0.625 mmol), palladium acetate (2.8 mg, 5 mol %), BINAP (15.3 mg, 10 mol %), TEBAC (56.7 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol), followed by toluene (0.5 mL). Refinement of the crude material by silica gel column chromatography (petroleum ether/ethyl acetate, 100:0 to 99:01) gave the indene 3ca (49.1 mg, 61%) as a light yellow jelly compound [TLC control (petroleum ether/ethyl acetate 100:0), Rf(2c) = 0.8, Rf(3ca) = 0.7, UV detection]. IR (MIR-ATR, 4000−600 cm−1): νmax = 2924, 2853, 1680, 1607, 1501, 1461, 1372, 1278, 1248, 1046, 824, 730, 701 cm−1. 1H NMR (CDCl3, 400 MHz): δ = 7.63 (d, 1H, J = 1.5 Hz, Ar−H), 7.60 (s, 1H, Ar−H), 7.53−7.46 (m, 2H, Ar− H), 7.41−7.36 (m, 3H, Ar−H), 7.29−7.24 (m, 2H, Ar−H), 7.23−7.19 (m, 1H, Ar−H), 7.18−7.07 (m, 3H, Ar−H), 3.08−3.05 (d, 1H, J = 14.7 Hz, CHaHb), 2.85−2.81 (d, 1H, J = 14.7 Hz, CHaHb), 2.00−1.67 (m, 2H, CH2-CH2−CH3), 1.19−0.75 (m, 2H, CH2-CH2−CH3), 0.68 (t, 3H, J = 7.3 Hz, CH2−CH2−CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 157.2 (s, Ar−C), 151.6 (s, Ar−C), 150.0 (s, Ar−C), 147.8 (s, Ar−C), 136.0 (s, Ar−C), 134.9 (s, Ar−C), 134.2 (s, Ar−C), 129.3 (d, 2C, 2 × Ar−CH), 128.3 (d, 2C, 2 × Ar−CH), 127.6 (d, Ar−CH), 127.3 (d, Ar−CH), 126.8 (s, Ar−C), 126.6 (d, Ar−CH), 125.9 (d, Ar−CH), 124.7 (d, Ar−CH), 122.9 (d, Ar−CH), 122.4 (d, Ar−CH), 120.9 (d, Ar−CH), 65.5 [s, C(CH2−CH3)CH2Ar], 42.6 [t, C(CH2CH2−CH3)CH2Ar], 39.8 [t, C(CH2−CH2−CH3)CH2Ar], 17.7 [t, C(CH2− CH2-CH3)CH2Ar], 14.4 [q, C(CH2−CH2−CH3)CH2Ar] ppm. HR-MS (APCI+) m/z calculated for [C25H23]+ = [M + H]+: 323.1794; found 323.1788. 4b-Propyl-8-(trifluoromethyl)-10-(3-(trifluoromethyl)phenyl)4b,5-dihydroindeno[2,1-a]indene (3ck). GP was carried out with 1bromo-2-(pent-1-en-2-yl)benzene 1c (56.2 mg, 0.25 mmol), 1,2-bis(3(trifluoromethyl)phenyl)ethyne 2k (196.2 mg, 0.625 mmol), palladium acetate (2.8 mg, 5 mol %), BINAP (15.3 mg, 10 mol %), TEBAC (56.7 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol), followed by toluene (0.5 mL). Refinement of the crude material by silica gel column chromatography (petroleum ether/ethyl acetate, 100:0 to 99:01) gave the indene 3ck (59.5 mg, 52%) as a light yellow jelly compound [TLC control (petroleum ether/ethyl acetate 100:0), Rf(2c) = 0.8, Rf(3ck) = 0.7, UV detection]. IR (MIR-ATR, 4000−600 cm−1): νmax = 3020, 2953, 2915, 2855, 2171, 2138, 1984, 1701, 1658, 1605, 1521, 1452, 1371, 1268, 1248, 1042, 820, 737 cm−1. 1H NMR (CDCl3, 400 MHz): δ = 7.88 (s, 1H, Ar−H), 7.81−7.79 (d, 1H, J = 4260


Article

The Journal of Organic Chemistry 7.3 Hz, Ar−H), 7.71−7.62 (m, 3H, Ar−H), 7.46−7.41 (m, 3H, Ar− H), 7.39−7.34 (m, 1H, Ar−H), 7.32−7.27 (m, 2H, Ar−H), 3.17−3.13 (d, 1H, J = 14.7 Hz, CHaHb), 2.88−2.84 (d, 1H, J = 14.7 Hz, CHaHb), 2.01−1.66 (m, 2H, CH2-CH2−CH3), 1.16−0.79 (m, 2H, CH2-CH2− CH3), 0.70 (t, 3H, J = 7.3 Hz, CH2−CH2−CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 156.5 (s, Ar−C), 155.4 (s, Ar−C), 149.8 (s, Ar−C), 146.6 (s, Ar−C), 136.0 (s, Ar−C), 135.1 (s, Ar−C), 134.5 (s, Ar−C), 132.2 (d, Ar−CH), 129.1 (d, 2C, 2 × Ar−CH), 127.3 (d, 2C, 2 × Ar−CH), 126.2 (d, 2C, 2 × Ar−CH), 126.0 (d, Ar−CH), 125.7 (d, 2C, 2 × Ar−CH), 124.8 (q, Ar−CF3), 123.2 (q, Ar−CF3), 121.0 (d, Ar−CH), 118.8 (d, Ar−CH), 66.1 [s, C(CH2−CH2−CH3)CH2Ar], 42.3 [t, C(CH2-CH2−CH3)CH2Ar], 39.9 [t, C(CH2−CH2− CH3)CH2Ar], 17.6 [t, C(CH2− CH2-CH3)CH2Ar], 14.3 [q, C(CH2− CH2−CH3)CH2Ar] ppm. HR-MS (APCI+) m/z calculated for [C27H21F6]+ = [M + H]+: 459.1542; found 459.1536. 4b-Isopropyl-10-phenyl-4b,5-dihydroindeno[2,1-a]indene (3da). GP was carried out with 1-bromo-2-(3-methylbut-1-en-2-yl)benzene 1d (56.2 mg, 0.25 mmol), 1,2-diphenylethyne 2a (111.2 mg, 0.625 mmol), palladium acetate (2.8 mg, 5 mol %), BINAP (15.3 mg, 10 mol %), TEBAC (56.7 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol), followed by toluene (0.5 mL). Refinement of the crude material by silica gel column chromatography (petroleum ether/ethyl acetate, 100:0 to 99:01) gave the indene 3da (48.3 mg, 60%) as a light yellow jelly compound [TLC control (petroleum ether/ethyl acetate 100:0), Rf(2c) = 0.8, Rf(3da) = 0.7, UV detection]. IR (MIR-ATR, 4000−600 cm−1): νmax = 2924, 2853, 1684, 1607, 1501, 1461, 1372, 1261, 1240, 1049, 889, 730 cm−1. 1H NMR (CDCl3, 400 MHz): δ = 7.60 (d, 2H, J = 8.3 Hz, Ar−H), 7.47 (t, 3H,, J = 7.3 and 6.8 Hz, Ar−H), 7.40−7.34 (m, 3H, Ar−H), 7.31−7.21 (m, 2H, Ar−H), 7.19−7.03 (m, 4H, Ar− H), 3.30−3.27 (d, 1H, J = 14.7 Hz, CHaHb), 2.83−2.79 (d, 1H, J = 14.7 Hz, CHaHb), 2.06−2.00 (m, 1H, [CH-(CH3)2], 1.15 (d, 3H, J = 6.8 Hz, [CH-(CH3)2], 0.53 (d, 3H, J = 6.8 Hz, [CH-(CH3)2] ppm. 13C NMR (CDCl3, 100 MHz): δ = 157.6 (s, Ar−C), 151.7 (s, Ar−C), 148.7 (s, Ar−C), 148.0 (s, Ar−C), 136.1 (s, Ar−C), 134.8 (s, Ar−C), 134.4 (s, Ar−C), 129.3 (d, 2C, 2 × Ar−CH), 128.3 (d, 2C, 2 × Ar− CH), 127.6 (d, Ar−CH), 127.3 (d, Ar−CH), 126.9 (s, Ar−C), 126.6 (d, Ar−CH), 125.8 (d, Ar−CH), 124.0 (d, 2C, 2 × Ar−CH), 122.0 (d, Ar−CH), 120.7 (d, Ar−CH), 66.6 [s, C(CH-(CH3)2)CH2Ar], 37.8 [t, C(CH-(CH3)2)CH2Ar], 35.4 [t, C(CH-(CH3)2)CH2Ar], 19.2 [t, C(CH-(CH3)2)CH2Ar], 17.3 [q, C(CH-(CH3)2)CH2Ar] ppm. HRMS (APCI+) m/z calculated for [C25H23]+ = [M + H]+: 323.1794; found 323.1789. 3-Methoxy-4b-methyl-10-phenyl-4b,5-dihydroindeno[2,1-a]indene (3ea). GP was carried out with 1-bromo-4-methoxy-2-(prop-1en-2-yl)benzene 1e (56.7 mg, 0.25 mmol), 1,2-diphenylethyne 2a (111.2 mg, 0.625 mmol), palladium acetate (2.8 mg, 5 mol %), BINAP (15.3 mg, 10 mol %), TEBAC (56.7 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol), followed by toluene (0.5 mL). Refinement of the crude material by silica gel column chromatography (petroleum ether/ethyl acetate, 100:0 to 99:01) gave the indene 3ea (48.3 mg, 60%) as a light yellow jelly compound [TLC control (petroleum ether/ethyl acetate 100:0), Rf(2c) = 0.8, Rf(3ea) = 0.7, UV detection]. IR (MIR-ATR, 4000−600 cm−1): νmax = 2924, 2853, 1734, 1683, 1607, 1501, 1461, 1371, 1268, 1248, 1042, 824, 737 cm−1. 1H NMR (CDCl3, 400 MHz): δ = 7.65 (s, 1H, Ar−H), 7.63 (s, 1H, Ar−H), 7.55−7.48(m, 2H, Ar− H), 7.42−7.38 (m, 1H, Ar−H), 7.35−7.29 (m, 2H, Ar−H), 7.17−7.09 (m, 3H, Ar−H), 7.06−7.05 (d, 1H, J = 2.4 Hz, Ar−H), 6.86−6.82 (dd, 1H, J = 8.3 and 2.4 Hz, Ar−H), 3.88 (s, 3H, ArOCH3), 3.05−3.01 (d, 1H, J = 14.7 Hz, CHaHb), 2.88−2.84 (d, 1H, J = 14.7 Hz, CHaHb), 1.45 (s, 3H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 158.1 (s, Ar−C), 156.6 (s, Ar−C), 153.3 (s, Ar−C), 150.6 (s, Ar−C), 139.5 (s, Ar−C), 135.9 (s, Ar−C), 135.0 (s, Ar−C), 133.0 (s, Ar−C), 129.3 (d, 2C, 2 × Ar−CH), 128.3 (d, 2C, 2 × Ar−CH), 127.6 (d, Ar−CH), 127.0 (d, Ar−CH), 126.7 (d, Ar−CH), 126.0 (d, Ar−CH), 122.3 (d, Ar−CH), 121.8 (d, Ar−CH), 111.6 (d, Ar−CH), 109.9 (d, Ar−CH), 61.5 [s, C(CH3)CH2Ar], 55.6 (q, ArOCH3), 40.2 [t, C(CH3)CH2Ar], 27.3 (q, CH3) ppm. HR-MS (APCI+) m/z calculated for [C24H21O]+ = [M + H]+: 325.1587; found 325.1594. 3-Methoxy-4b,7-dimethyl-10-(p-tolyl)-4b,5-dihydroindeno[2,1a]indene (3eb). GP was carried out with 1-bromo-4-methoxy-2-(prop-

1-en-2-yl)benzene 1e (56.7 mg, 0.25 mmol), 1,2-di-p-tolylethyne 2b (128.7 mg, 0.625 mmol), palladium acetate (2.8 mg, 5 mol %), BINAP (15.3 mg, 10 mol %), TEBAC (56.7 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol), followed by toluene (0.5 mL). Refinement of the crude material by silica gel column chromatography (petroleum ether/ethyl acetate, 95:5 to 99:1) gave the indene 3eb (70 mg, 73%) as a light yellow jelly compound [TLC control (petroleum ether/ethyl acetate 95:5), Rf(2c) = 0.7, Rf(3eb) = 0.6, UV detection]. IR (MIR-ATR, 4000−600 cm−1): νmax = 2924, 2853, 1683, 1607, 1501, 1461, 1372, 1268, 1248, 1045, 824, 801, 747 cm−1.1H NMR (CDCl3, 400 MHz): δ = 7.53 (s, 1H, Ar−H), 7.51 (s, 1H, Ar−H), 7.43 (d, 1H, J = 7.8 Hz, Ar−H), 7.29 (d, 3H, J = 7.8 Hz, Ar−H), 7.12 (s, 1H, Ar−H), 7.03 (d, 1H, J = 2.4 Hz, Ar−H), 6.02 (d, 1H, J = 7.8 Hz, Ar−H), 6.82−6.80 (dd, 1H, J = 8.3 and 2.4 Hz, Ar−H), 3.87 (s, 3H, ArOCH3), 2.98−2.95 (d, 1H, J = 14.2 Hz, CHaHb), 2.83−2.79 (d, 1H, J = 14.2 Hz, CHaHb), 2.43 (s, 3H, ArCH3), 2.32 (s, 3H, ArCH3), 1.42 (d, 3H, J = 4.9 Hz, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 157.9 (s, Ar−C), 156.3 (s, Ar−C), 153.2 (s, Ar−C), 150.9 (s, Ar−C), 139.8 (s, Ar−C), 137.1 (s, Ar−C), 136.9 (s, Ar−C), 133.3 (s, Ar−C), 132.1 (s, Ar−C), 132.0 (s, Ar−C), 129.1 (d, 2C, 2 × Ar−CH), 128.9 (d, 2C, 2 × Ar−CH), 127.4 (d, Ar−CH), 126.8 (d, Ar−CH), 122.0 (d, Ar−CH), 121.6 (d, Ar−CH), 111.5 (d, Ar−CH), 109.9 (d, Ar−CH), 61.5 [s, C(CH3)CH2Ar], 55.6 (q, 3H, ArOCH3), 40.1 [t, C(CH3)CH2Ar], 27.4 (q, CH3), 21.5 (q, ArCH3), 21.4 (q, ArCH3) ppm. HR-MS (APCI+) m/z calculated for [C26H25O]+ = [M + H]+: 353.1900; found 353.1899. 3-Methoxy-4b,8-dimethyl-10-(m-tolyl)-4b,5-dihydroindeno[2,1a]indene (3ec). GP was carried out with 1-bromo-4-methoxy-2-(prop1-en-2-yl)benzene 1e (56.7 mg, 0.25 mmol), 1,2-di-m-tolylethyne 2c (128.7 mg, 0.625 mmol), palladium acetate (2.8 mg, 5 mol %), BINAP (15.3 mg, 10 mol %), TEBAC (56.7 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol), followed by toluene (0.5 mL). Refinement of the crude material by silica gel column chromatography (petroleum ether/ethyl acetate, 95:5 to 99:1) gave the indene 3ec (62.4 mg, 71%) as a light yellow jelly compound [TLC control (petroleum ether/ethyl acetate 95:5), Rf(2c) = 0.7, Rf(3ec) = 0.6, UV detection]. IR (MIR-ATR, 4000−600 cm−1): νmax = 2924, 2853, 1734, 1683, 1607, 1501, 1461, 1371, 1268, 1248, 1042, 824, 737 cm−1. 1H NMR (CDCl3, 400 MHz): δ = 7.46−7.37 (m, 3H, Ar−H), 7.35−7.29 (m, 2H, Ar−H), 7.22−7.17 (m, 2H, Ar−H), 7.04 (d, 1H, J = 2.4 Hz, Ar−H), 6.96 (d, 1H, J = 7.3 Hz, Ar−H), 6.82 (dd, 1H, J = 8.3 and 2.0 Hz, Ar−H), 3.87 (s, 3H, ArOCH3), 2.99−2.95 (d, 1H, J = 14.7 Hz,, CHaHb), 2.81−2.78 (d, 1H, J = 14.7 CHaHb), 2.45 (s, 3H, ArCH3), 2.28 (s, 3H, ArCH3), 1.42 (s, 3H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 158.0 (s, Ar−C), 156.6 (s, Ar−C), 153.3 (s, Ar−C), 147.7 (s, Ar−C), 139.6 (s, Ar−C), 137.8 (s, Ar−C), 136.2 (s, Ar−C), 136.0 (s, Ar−C), 135.0 (s, Ar−C), 132.8 (s, Ar−C), 129.9 (d, Ar−CH), 128.3 (d, Ar−CH), 128.2 (d, Ar−CH), 127.9 (d, Ar−CH), 126.5 (d, Ar−CH), 125.6 (d, Ar−CH), 123.0 (d, Ar−CH), 121.7 (d, Ar−CH), 111.5 (d, Ar−CH), 109.8 (d, Ar−CH), 61.8 [s, C(CH3)CH2Ar], 55.6 (q, 3H, ArOCH3), 39.8 [t, C(CH3)CH2Ar], 27.3 (q, CH3), 21.5 (q, ArCH3), 21.5 (q, ArCH3) ppm. HR-MS (APCI+) m/z calculated for [C26H25O]+ = [M + H]+: 353.1900; found 353.1911. 7-Methoxy-10-(4-methoxyphenyl)-4b-methyl-4b,5dihydroindeno[2,1-a]indene (3ed). GP was carried out with 1bromo-4-methoxy-2-(prop-1-en-2-yl)benzene 1e (49.2 mg, 0.25 mmol), 1,2-bis(4-methoxyphenyl)ethyne 2d (148.7 mg, 0.625 mmol), palladium acetate (2.8 mg, 5 mol %), BINAP (15.3 mg, 10 mol %), TEBAC (56.7 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol), followed by toluene (0.5 mL). Refinement of the crude material by silica gel column chromatography (petroleum ether/ethyl acetate, 92:8 to 94:6) gave the indene 3ed (60.7 mg, 69%) as a light yellow jelly compound [TLC control (petroleum ether/ethyl acetate 92:8), Rf(2c) = 0.6, Rf(3ed) = 0.5, UV detection]. IR (MIR-ATR, 4000−600 cm−1): νmax = 2928, 2854, 1687, 1607, 1501, 1461, 1371, 1268, 1248, 1042, 820, 737 cm−1. 1H NMR (CDCl3, 400 MHz): δ = 7.55 (s, 1H, Ar−H), 7.53 (s, 1H, Ar−H), 7.43 (d, 1H, J = 8.3 Hz, Ar−H), 7.27−7.25 (d, 1H, J = 8.8 Hz, Ar−H), 7.01 (d, 3H, J = 7.8 Hz Ar−H), 6.86 (s, 1H, Ar−H), 6.80 (d, 1H, J = 8.3 Hz, Ar−H), 6.65 (d, 1H, J = 8.3 Hz, Ar− H), 3.87 (s, 3H, ArOCH3), 3.86 (s, 3H, ArOCH3), 3.78 (s, 3H, ArOCH3), 2.98−2.94 (d, 1H, J = 14.2 Hz, CHaHb), 2.83−2.79 (d, 1H, 4261


Article

The Journal of Organic Chemistry J = 14.2 Hz, CHaHb), 1.40 (s, 3H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 159.2 (s, Ar−C), 158.9 (s, Ar−C), 157.8 (s, Ar−C), 155.6 (s, Ar−C), 153.0 (s, Ar−C), 152.5 (s, Ar−C), 140.0 (s, Ar−C), 130.6 (s, Ar−C), 130.3 (d, 2C, 2 × Ar−CH), 129.0 (s, Ar−C), 127.6 (s, Ar− C), 122.8 (d, Ar−CH), 121.3 (d, Ar−CH), 113.7 (d, 2C, 2 × Ar− CH), 112.2 (d, Ar−CH), 111.9 (d, Ar−CH), 111.4 (d, Ar−CH), 109.9 (d, Ar−CH), 61.6 [s, C(CH3)CH2Ar], 55.6 (q, 3H, ArOCH3), 55.4 (q, 3H, ArOCH3), 55.3 (q, 3H, ArOCH3), 40.3 [t, C(CH3) CH2Ar], 27.6 (q, 3H, CH3) ppm. HR-MS (APCI+) m/z calculated for [C26H25O3]+ = [M + H]+: 385.1798; found 385.1798. 2,3-Dimethoxy-4b-methyl-10-phenyl-4b,5-dihydroindeno[2,1-a]indene (3fa). GP was carried out with 1-bromo-4,5-dimethoxy-2(prop-1-en-2-yl)benzene 1f (64.2 mg, 0.25 mmol), 1,2-diphenylethyne 2a (111.2 mg, 0.625 mmol), palladium acetate (2.8 mg, 5 mol %), BINAP (15.3 mg, 10 mol %), TEBAC (56.7 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol), followed by toluene (0.5 mL). Refinement of the crude material by silica gel column chromatography (petroleum ether/ ethyl acetate, 90:10 to 91:09) gave the indene 3fa (57.5 mg, 65%) as a light yellow jelly compound [TLC control (petroleum ether/ethyl acetate 90:10), Rf(2c) = 0.5, Rf(3fa) = 0.4, UV detection]. IR (MIRATR, 4000−600 cm−1): νmax = 3015, 2924, 2853, 1734, 1683, 1607, 1511, 1461, 1371, 1265, 1248, 1042, 825, 734 cm−1.1H NMR (CDCl3, 400 MHz): δ = 7.63 (d, 1H, Ar−H), 7.61 (d, 1H, Ar−H), 7.52−7.48 (t, 3H, J = 7.8 and 7.3 Hz, Ar−H), 7.42−7.38 (m, 1H, Ar−H), 7.28 (d, 1H, J = 7.3 Hz Ar−H), 7.14−7.08 (m, 2H, Ar−H), 7.03 (s, 1H, Ar− H), 6.93 (s, 1H, Ar−H), 3.96 (s, 3H, ArOCH3), 3.85 (s, 3H, ArOCH3), 3.02−2.98 (d, 1H, J = 14.2 Hz, CHaHb), 2.82−2.78 (d, 1H, J = 14.2 Hz, CHaHb), 1.42 (s, 3H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 157.7 (s, Ar−C), 150.9 (s, Ar−C), 148.4 (s, Ar−C), 147.5 (s, Ar−C), 144.1 (s, Ar−C), 139.0 (s, Ar−C), 135.8 (s, Ar−C), 135.1 (s, Ar−C), 133.2 (s, Ar−C), 129.2 (d, 2C, 2 × Ar−CH), 128.4 (s, 2C, 2 × Ar−CH), 127.6 (d, Ar−CH), 127.0 (d, Ar−CH), 126.7 (d, Ar− CH), 125.9 (d, Ar−CH), 122.2 (d, Ar−CH), 107.2 (d, Ar−CH), 105.1 (d, Ar−CH), 61.8 [s, C(CH3)CH2Ar], 56.3 (q, 3H, ArOCH3), 56.2 (q, 3H, ArOCH3), 40.5 [t, C(CH3)CH2Ar], 27.2 (q, CH3) ppm. HR-MS (APCI+) m/z calculated for [C25H23O2]+ = [M + H]+: 355.1693; found 355.1692. 2,3-Dimethoxy-4b,7-dimethyl-10-(p-tolyl)-4b,5-dihydroindeno[2,1-a]indene (3fb). GP was carried out with 1-bromo-4,5-dimethoxy2-(prop-1-en-2-yl)benzene 1f (64.2 mg, 0.25 mmol), 1,2-di-ptolylethyne 2b (128.7 mg, 0.625 mmol), palladium acetate (2.8 mg, 5 mol %), BINAP (15.3 mg, 10 mol %), TEBAC (56.7 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol), followed by toluene (0.5 mL). Refinement of the crude material by silica gel column chromatography (petroleum ether/ethyl acetate, 89:11 to 90:10) gave the indene 3fb (53.7 mg, 64%) as a light yellow jelly compound [TLC control (petroleum ether/ethyl acetate 89:11), Rf(2c) = 0.5, Rf(3fb) = 0.4, UV detection]. IR (MIR-ATR, 4000−600 cm−1): νmax = 2924, 2854, 1714, 1684, 1607, 1511, 1461, 1372, 1261, 1249, 1043, 825, 741 cm−1. 1H NMR (CDCl3, 400 MHz): δ = 7.52 (s, 1H, Ar−H), 7.50 (s, 1H, Ar− H), 7.41−7.39 (d, 1H, J = 7.3 Hz, Ar−H), 7.31−7.29 (d, 2H, J = 7.3 Hz, Ar−H), 7.10 (s, 1H, Ar−H), 7.02 (s, 1H, Ar−H), 6.94 (s, 1H, Ar− H), 6.90 (d, 1H, J = 7.8 Hz, Ar−H), 3.95 (s, 3H, ArOCH3), 3.85 (s, 3H, ArOCH3), 2.96−2.93 (d, 1H, J = 14.2 Hz, CHaHb), 2.78−2.75 (d, 1H, J = 14.2 Hz, CHaHb), 2.43 (s, 3H, ArCH3), 2.31 (s, 3H, ArCH3), 1.41 (s, 3H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 157.4 (s, Ar−C), 151.1 (s, Ar−C), 147.2 (s, Ar−C), 143.9 (s, Ar−C), 139.2 (s, Ar−C), 137.1 (s, Ar−C), 136.8 (s, Ar−C), 133.2 (s, Ar−C), 132.1 (s, Ar−C), 129.1 (s, 5C, 5 × Ar−CH), 129.0 (s, Ar−C), 127.4 (d, Ar− CH), 126.7 (d, Ar−CH), 121.9 (d, Ar−CH), 107.1 (d, Ar−CH), 104.9 (d, Ar−CH), 61.7 [s, C(CH3)CH2Ar], 56.3 (q, 3H, ArOCH3), 56.2 (q, 3H, ArOCH3), 40.4 [t, C(CH3)CH2Ar], 27.3 (q, CH3), 21.5 (q, 3H, ArCH3), 21.4 (q, 3H, ArCH3) ppm. HR-MS (APCI+) m/z calculated for [C27H27O2]+ = [M + H]+: 383.2006; found 383.2011. 10-(3,4-Dimethoxyphenyl)-2,3,7,8-tetramethoxy-4b-methyl-4b,5dihydroindeno[2,1-a]indene (3fj). GP was carried out with 1-bromo4,5-dimethoxy-2-(prop-1-en-2-yl)benzene 1f (64.2 mg, 0.25 mmol), 1,2-bis(4-methoxyphenyl)ethyne 2j (186 mg, 0.625 mmol), palladium acetate (2.8 mg, 5 mol %), BINAP (15.3 mg, 10 mol %), TEBAC (56.7 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol), followed by toluene

(0.5 mL). Refinement of the crude material by silica gel column chromatography (petroleum ether/ethyl acetate, 35:65 to 40:60) gave the indene 3fj (72.2 mg, 61%) as a light yellow jelly compound [TLC control (petroleum ether/ethyl acetate 35:65), Rf(2c) = 0.7, Rf(3fj) = 0.5, UV detection]. IR (MIR-ATR, 4000−600 cm−1): νmax = 3125, 2953, 2910, 2857, 2171, 2138, 1984, 1709, 1658, 1605, 1521, 1452, 1371, 1268, 1249, 1043, 825, 731 cm−1. 1H NMR (CDCl3, 400 MHz): δ = 7.20−7.18 (dd, 1H, J = 7.8 and 1.5 Hz, Ar−H), 7.15 (d, 1H, J = 2.0 Hz, Ar−H), 7.07 (s, 1H, Ar−H), 7.01 (t, 2H, J = 7.8 and 3.4 Hz, Ar− H), 6.94 (s, 1H, Ar−H), 6.86 (s, 1H, Ar−H), 3.95 (s, 2 × 3H, 2 × ArOCH3), 3.91 (s, 3H, ArOCH3), 3.87 (s, 3H, ArOCH3), 3.85 (s, 3H, ArOCH3), 3.77 (s, 3H, ArOCH3), 2.93−2.90 (d, 1H, J = 14.2 Hz, CHaHb), 2.79−2.75 (d, 1H, J = 14.2 Hz, CHaHb), 1.42 (s, 3H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 157.4 (s, Ar−C), 148.7 (s, Ar−C), 148.6 (s, Ar−C), 148.4 (s, Ar−C), 148.3 (s, Ar−C), 147.9 (s, Ar−C), 147.0 (s, Ar−C), 143.7 (S, Ar−C), 143.6 (S, Ar−C), 139.3 (s, Ar−C), 130.3 (s, Ar−C), 128.3 (s, Ar−C), 127.9 (s, Ar−C), 121.5 (d, Ar−CH), 112.0 (d, Ar−CH), 111.0 (d, Ar−CH), 109.4 (d, Ar−CH), 107.2 (d, Ar−CH), 105.5 (d, Ar−CH), 104.7 (d, Ar−CH), 62.1 [s, C(CH3)CH2Ar], 56.4 (q, 3H, ArOCH3), 56.1 (q, 3H, ArOCH3), 56.0 (q, 3H, ArOCH3), 55.9 (q, 6H, 2 × ArOCH3), 40.1 [t, C(CH3) CH2Ar], 28.0 (q, CH3) ppm. HR-MS (APCI+) m/z calculated for [C29H30O6]+ = [M + H]+: 474.5449; found 474.5426. 3 - (B e n zy lo x y ) - 2- m e tho x y - 4 b- m e th y l - 10 - p h e n y l - 4b , 5 dihydroindeno[2,1-a]indene (3ga). GP was carried out with 1(benzyloxy)-4-bromo-2-methoxy-5-(prop-1-en-2-yl)benzene 1g (83.2 mg, 0.25 mmol), 1,2-diphenylethyne 2a (111.2 mg, 0.625 mmol), palladium acetate (2.8 mg, 5 mol %), BINAP (15.3 mg, 10 mol %), TEBAC (56.7 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol), followed by toluene (0.5 mL). Refinement of the crude material by silica gel column chromatography (petroleum ether/ethyl acetate, 80:0 to 85:15) gave the indene 3ga (66.6 mg, 62%) as a light yellow jelly compound [TLC control (petroleum ether/ethyl acetate 80:20), Rf(2c) = 0.6, Rf(3ga) = 0.5, UV detection]. IR (MIR-ATR, 4000−600 cm−1): νmax = 2928, 2854, 1734, 1683, 1607, 1501, 1461, 1372, 1268, 1245, 1043, 824, 809, 737, 721 cm−1. 1H NMR (CDCl3, 400 MHz): δ = 7.64 (s, 1H, Ar−H), 7.62 (s, 1H, Ar−H), 7.53−7.49 (m, 5H, Ar− H), 7.42−7.37 (m, 3H, Ar−H), 7.34−7.26 (m, 3H, Ar−H), 7.15−7.06 (m, 3H, Ar−H), 6.97 (s, 1H, Ar−H), 5.21 (s, 2H, Ar-OCH2−), 3.86 (s, 3H, ArOCH3), 2.98−2.95 (d, 1H, J = 14.7 Hz,, CHaHb), 2.78−2.75 (d, 1H, J = 14.7 CHaHb), 1.37 (s, 3H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 158.0 (s, Ar−C), 151.0 (s, Ar−C), 149.4 (s, Ar−C), 146.6 (s, Ar−C), 144.0 (s, Ar−C), 139.9 (s, Ar−C), 137.5 (s, Ar−C), 135.8 (s, Ar−C), 135.0 (s, Ar−C), 133.1 (s, Ar−C), 129.2 (d, 2C, 2 × Ar−CH), 128.5 (d, 2C, 2 × Ar−CH), 128.4 (d, 2C, 2 × Ar−CH), 127.8 (d, Ar−CH), 127.6 (d, 2C, 2 × Ar−CH), 127.5 (d, Ar−CH), 127.0 (d, Ar−CH), 126.7 (d, Ar−CH), 125.9 (d, Ar−CH), 122.2 (d, Ar−CH), 110.6 (d, Ar−CH), 105.8 (d, Ar−CH), 71.9 (t, 2H, ArOCH2), 61.7 [s, C(CH3)CH2Ar], 56.4 (q, 3H, ArOCH3), 40.4 [t, C(CH3)CH2Ar], 27.1 (q, CH3) ppm.HR-MS (APCI+) m/z calculated for [C31H27O2]+ = [M + H]+: 432.2039; found 432.2051. 3-(Benzyloxy)-2,7-dimethoxy-10-(4-methoxyphenyl)-4b-methyl4b,5-dihydroindeno[2,1-a]indene (3gd). GP was carried out with 1(benzyloxy)-4-bromo-2-methoxy-5-(prop-1-en-2-yl)benzene 1g (83.2 mg, 0.25 mmol), 1,2-bis(4-methoxyphenyl)ethyne 2d (148.7 mg, 0.625 mmol), palladium acetate (2.8 mg, 5 mol %), BINAP (15.3 mg, 10 mol %), TEBAC (56.7 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol), followed by toluene (0.5 mL). Refinement of the crude material by silica gel column chromatography (petroleum ether/ethyl acetate, 70:30 to 80:20) gave the indene 3gd (83.3 mg, 68%) as a light yellow jelly compound [TLC control (petroleum ether/ethyl acetate 70:30), Rf(2c) = 0.7, Rf(3gd) = 0.5, UV detection]. IR (MIR-ATR, 4000−600 cm−1): νmax = 2923, 2854, 1734, 1683, 1607, 1521, 1461, 1371, 1263, 1241, 1046, 828, 731 cm−1. 1H NMR (CDCl3, 400 MHz): δ = 7.59 (s, 1H, Ar−H), 7.57 (s, 1H, Ar−H), 7.53 (s, 1H, Ar−H), 7.51 (s, 1H, Ar−H), 7.46−7.42 (m, 1H, Ar−H), 7.41−7.38 (m, 1H, Ar− H), 7.35−7.31 (m, 1H, Ar−H), 7.07 (d, 1H, J = 2.0 Hz, Ar−H), 7.05 (s, 1H, Ar−H), 6.88 (s, 1H, Ar−H), 6.69−6.66 (dd, 1H, J = 8.3 and 2.4 Hz, Ar−H) 5.22 (s, 2H, Ar-OCH2−), 3.89 (s, 3H, ArOCH3), 3.89 (s, 3H, ArOCH3), 3.79 (s, 3H, ArOCH3), 2.96−2.92 (d, 1H, J = 14.2 4262


Article

The Journal of Organic Chemistry Hz, CHaHb), 2.79−2.76 (d, 1H, J = 14.2 CHaHb), 1.39 (s, 3H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 159.2 (s, Ar−C), 158.9 (s, Ar−C), 156.9 (s, Ar−C), 152.8 (s, Ar−C), 149.3 (s, Ar−C), 146.1 (s, Ar−C), 143.6 (s, Ar−C), 140.3 (s, Ar−C), 137.4 (s, Ar−C), 130.6 (s, Ar−C), 130.3 (d, 2C, 2 × Ar−CH), 128.8 (s, Ar−C), 128.4 (d, 2C, 2 × Ar−CH), 127.8 (d, Ar−CH), 127.5 (d, 3C, 3 × Ar−CH), 122.7 (d, Ar−CH), 113.8 (d, 2C, 2 × Ar−CH), 112.2 (d, Ar−CH), 111.9 (d, Ar−CH), 110.6 (d, Ar−CH), 105.4 (d, Ar−CH), 71.9 (t, 2H, ArOCH2), 61.6 [s, C(CH3)CH2Ar], 56.3 (q, 3H, ArOCH3), 55.3 (q, 3H, ArOCH3), 55.2 (q, 3H, ArOCH3), 40.5 [t, C(CH3)CH2Ar], 27.5 (q, CH3) ppm.HR-MS (APCI+) m/z calculated for [C33H31O4]+ = [M + H]+: 491.2217; found 491.2210. 3-Fluoro-4b-methyl-10-phenyl-4b,5-dihydroindeno[2,1-a]indene (3ha). GP was carried out with 1-bromo-4-fluoro-2-(prop-1-en-2yl)benzene 1h (53.7 mg, 0.25 mmol), 1,2-diphenylethyne 2a (111.2 mg, 0.625 mmol), palladium acetate (2.8 mg, 5 mol %), BINAP (15.3 mg, 10 mol %), TEBAC (56.7 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol), followed by toluene (0.5 mL). Refinement of the crude material by silica gel column chromatography (petroleum ether/ethyl acetate, 100:0 to 99:01) gave the indene 3ha (46.8 mg, 60%) as a light yellow jelly compound [TLC control (petroleum ether/ethyl acetate 100:0), Rf(2c) = 0.8, Rf(3ha) = 0.7, UV detection]. IR (MIR-ATR, 4000−600 cm−1): νmax = 2925, 2854, 1683, 1607, 1501, 1462, 1372, 1261, 1249, 1045, 827, 735 cm−1. 1H NMR (CDCl3, 400 MHz): δ = 7.63 (d, 2H, J = 8.3 Hz, Ar−H), 7.55−7.49 (m, 3H, Ar−H), 7.43−7.39 (m, 1H, Ar−H), 7.34−7.29 (m, 2H, Ar−H), 7.19−7.11 (m, 4H, Ar− H), 7.01−6.96 (m, 1H, Ar−H), 3.06−3.03 (d, 1H, J = 14.7 Hz, CHaHb), 2.87−2.84 (d, 1H, J = 14.7 Hz, CHaHb), 1.45 (s, 3H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 162.7 (s, Ar−C, Jc‑f = 244.4), 158.3 (s, Ar−C), 153.4 (s, Ar−C), 150.7 (s, Ar−C), 142.4 (s, Ar−C), 135.5 (s, Ar−C), 134.6 (s, Ar−C), 132.5 (s, Ar−C), 129.2 (d, 2C, 2 × Ar−CH), 128.4 (d, 2C, 2 × Ar−CH), 127.8 (d, Ar−CH), 127.5 (d, Ar−CH), 126.8 (d, Ar−CH), 126.1 (d, Ar−CH), 122.5 (d, Ar−CH), 121.9 (d, Ar−CH), 113.6 (d, Ar−CH), 110.9 (d, Ar−CH), 61.6 [s, C(CH3)CH2Ar], 40.1 [t, C(CH3)CH2Ar], 27.1 (q, CH3) ppm. HRMS (APCI+) m/z calculated for [C23H17F]+ = [M + H]+: 312.3795; found 312.3791. 4b,7-Dimethyl-10-(4-methylphenyl)-4b,5-dihydroindeno[2,1-a]indene (3ia). GP was carried out with 1-Chloro-2-(prop-1-en-2yl)benzene 1i (38 mg, 0.25 mmol), 1,2-diphenylethyne 2a (111.2 mg, 0.62 mmol), palladium acetate (2.8 mg, 5 mol %), BINAP (15.3 mg, 10 mol %), TEBAC (56.7 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol), and toluene (0.5 mL). Refinement of the crude material by silica gel column chromatography (petroleum ether/ethyl acetate, 100:0 to 99:1) gave the indene 3aa (29.5 mg, 40%) as a light yellow jelly compound [TLC control (petroleum ether/ethyl acetate 100:0), Rf(2c) = 0.9, Rf(3aa) = 0.8, UV detection]. IR (MIR-ATR, 4000−600 cm−1): νmax = 3025, 2952, 2909, 2862, 2174, 2142, 1986, 1700, 1658, 1605, 1522, 1422, 1372, 1270, 1248, 1042, 824, 737 cm−1. 1H NMR (CDCl3, 400 MHz): δ = 7.62 (d, 2H, J = 6.8 Hz, Ar−H), 7.52 (d, 1H, J = 6.8 Hz, Ar−H), 7.50−7.43 (m, 3H, Ar−H), 7.40−7.36 (m, 2H, Ar−H), 7.30−7.19 (m, 3H, Ar−H), 7.16−7.07 (m, 2H, Ar−H), 3.05− 3.01 (d, 1H, J = 14.7 Hz, CHaHb), 2.84−2.80 (d, 1H, J = 14.7 Hz, CHaHb), 1.44 (s, 3H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 158.7 (s, Ar−C), 151.4 (s, Ar−C), 151.2 (s, Ar−C), 146.6 (s, Ar−C), 135.6 (s, Ar−C), 134.8 (s, Ar−C), 133.1 (s, Ar−C), 129.3 (d, 2C, 2 × Ar−CH), 128.3 (d, 2C, 2 × Ar−CH), 127.6 (d, Ar−CH), 127.4 (d, Ar−CH), 126.9 (d, Ar−CH), 126.7 (d, Ar−CH), 126.0 (d, Ar−CH), 125.0 (d, Ar−CH), 122.8 (d, Ar−CH), 122.7 (d, Ar−CH), 121.3 (d, Ar−CH), 61.8 [s, C(CH3)CH2Ar], 40.2 [t, C(CH3)CH2Ar], 27.1 (q, CH3) ppm. HR-MS (APCI+) m/z calculated for [C23H19]+ = [M + H]+: 295.1481; found 295.1475. 4b,7-Dimethyl-10-(4-methylphenyl)-4b,5-dihydroindeno[2,1-a]indene (3ja). GP was carried out with 1-iodo-2-(prop-1-en-2yl)benzene 1j (56 mg, 0.25 mmol), 1,2-diphenylethyne 2a (111.2 mg, 0.62 mmol), palladium acetate (2.8 mg, 5 mol %), BINAP (15.3 mg, 10 mol %), TEBAC (56.7 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol) and toluene (0.5 mL). Refinement of the crude material by silica gel column chromatography (petroleum ether/ethyl acetate, 100:0 to 99:1) gave the indene 3aa (44 mg, 60%) as a light yellow jelly

compound [TLC control (petroleum ether/ethyl acetate 100:0), Rf(2c) = 0.9, Rf(3aa) = 0.8, UV detection]. IR (MIR-ATR, 4000−600 cm−1): νmax = 3025, 2953, 2910, 2859, 2171, 2138, 1984, 1701, 1658, 1605, 1521, 1452, 1371, 1268, 1248, 1042, 824, 737 cm−1. 1H NMR (CDCl3, 400 MHz): δ = 7.62 (d, 2H, J = 6.8 Hz, Ar−H), 7.52 (d, 1H, J = 6.8 Hz, Ar−H), 7.50−7.43 (m, 3H, Ar−H), 7.40−7.36 (m, 2H, Ar−H), 7.30−7.19 (m, 3H, Ar−H), 7.16−7.07 (m, 2H, Ar−H), 3.05− 3.01 (d, 1H, J = 14.7 Hz, CHaHb), 2.84−2.80 (d, 1H, J = 14.7 Hz, CHaHb), 1.44 (s, 3H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 158.7 (s, Ar−C), 151.4 (s, Ar−C), 151.2 (s, Ar−C), 146.6 (s, Ar−C), 135.6 (s, Ar−C), 134.8 (s, Ar−C), 133.1 (s, Ar−C), 129.3 (d, 2C, 2 × Ar−CH), 128.3 (d, 2C, 2 × Ar−CH), 127.6 (d, Ar−CH), 127.4 (d, Ar−CH), 126.9 (d, Ar−CH), 126.7 (d, Ar−CH), 126.0 (d, Ar−CH), 125.0 (d, Ar−CH), 122.8 (d, Ar−CH), 122.7 (d, Ar−CH), 121.3 (d, Ar−CH), 61.8 [s, C(CH3)CH2Ar], 40.2 [t, C(CH3)CH2Ar], 27.1 (q, CH3) ppm. HR-MS (APCI+) m/z calculated for [C23H19]+ = [M + H]+: 295.1481; found 295.1476. Methyl 8-Methoxy-9b-methyl-5-phenyl-9b,10-dihydroindeno[2,1-a]indene-2-carboxylate (3ei). GP was carried out with 1bromo-4-methoxy-2-(prop-1-en-2-yl)benzene 1e (56.7 mg, 0.25 mmol), methyl 4-(phenylethynyl)benzoate 2i (147.5 mg, 0.625 mmol), palladium acetate (2.8 mg, 5 mol %), BINAP (15.3 mg, 10 mol %), TEBAC (56.7 mg, 0.25 mmol), K2CO3 (138.6 mg, 1 mmol), followed by toluene (0.5 mL). Refinement of the crude material by silica gel column chromatography (petroleum ether/ethyl acetate, 90:10 to 91:9) gave the indene 3ei (52 mg, 55%) as a light yellow jelly compound [TLC control (petroleum ether/ethyl acetate 91:9), Rf(2c) = 0.6, Rf(3ai) = 0.5, UV detection]. IR (MIR-ATR, 4000−600 cm−1): νmax= 2952, 2911, 2859, 2161, 2137, 1984, 1735, 1711, 1658, 1615, 1521, 1381, 1268, 1238, 1032, 829, cm−1. 1H NMR (CDCl3, 400 MHz): δ = 7.93 (s, 1H, Ar−H), 7.79 (d, 1H, J = 7.8 Hz, Ar−H), 7.61 (d, 2H, J = 7.3 Hz, Ar−H), 7.53−7.48 (m, 3H, Ar−H), 7.41 (t, 2H, J = 7.3 and 6.35 Hz, Ar−H), 7.31 (d, 1H, J = 8.3 Hz, Ar−H), 7.03 (d, 1H, J = 2.44 Hz, Ar−H), 6.84−6.81 (dd, 1H, J = 8.3 and 2.2 Hz, Ar−H), 3.88 (s, 3H, Ar-OMe), 3.87 (s, 3H, Ar−COOMe), 3.08−3.04 (d, 1H, J = 14.7 Hz, CHaHb), 2.86−2.83 (d, 1H, J = 14.7 Hz, CHaHb), 1.41 (s, 3H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 167.2 (s, Ar−C), 158.6 (s, Ar−C), 155.2 (s, Ar−C), 153.5 (s, Ar−C), 150.6 (s, Ar−C), 140.5 (s, Ar−C), 139.1 (s, Ar−C), 135.6 (s, Ar−C), 134.5 (s, Ar−C), 129.2 (d, 2C, 2 × Ar−CH), 129.1 (d, 2C, 2 × Ar−CH), 128.8 (d, Ar− CH), 128.5 (d, Ar−CH), 128.3 (d, Ar−CH), 128.1 (d, Ar−CH), 126.8 (d, Ar−CH), 122.4 (d, Ar−CH), 121.8 (d, Ar−CH), 112.0 (d, Ar−CH), 109.9 (d, Ar−CH), 61.8 [s, C(CH3)CH2Ar], 55.6 (q, ArOCH3), 52.1 (q, ArCOOCH3), 40.2 [t, C(CH3)CH2Ar], 27.1 (q, CH3) ppm. HR-MS (APCI+) m/z calculated for [C26H22O3]+ = [M + H]+: 382.1569; found 382.1568.

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ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.joc.7b00254. List of starting materials and NMR spectra for all new compounds (PDF) X-ray diffraction analysis data (CIF)

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AUTHOR INFORMATION

Corresponding Author

*Phone: (040) 2301 6033. Fax: (040) 2301 6003/32. E-mail: [email protected] ORCID

Gedu Satyanarayana: 0000-0002-6410-5421 Notes

The authors declare no competing financial interest. 4263


Article

The Journal of Organic Chemistry

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2005, 44, 4046. (c) Wang, G.-W.; Yuan, T.-T.; Li, D.-D. Angew. Chem., Int. Ed. 2011, 50, 1380. (d) Chinnagolla, R. K.; Jeganmohan, M. Chem. Commun. 2014, 50, 2442. (e) Warratz, S.; Kornhaaß, C.; Cajaraville, A.; Niepötter, B.; Stalke, D.; Ackermann, L. Angew. Chem., Int. Ed. 2015, 54, 1. (f) Ritleng, V.; Sirlin, C.; Pfeffer, M. Chem. Rev. 2002, 102, 1731. (g) Xu, X.; Deng, Y.; Yim, D. N.; Zavalij, P. Y.; Doyle, M. P. Chem. Sci. 2015, 6, 2196. (11) (a) Das, P.; Mcleod, D.; Mcnulty, J. Tetrahedron Lett. 2011, 52, 199. (b) Gagnier, S. V.; Larock, R. C. J. Am. Chem. Soc. 2003, 125, 4804. (c) Fang, J.; Ren, J.; Wang, Z. Org. Lett. 2015, 17, 4180. (12) (a) Jeffery, T. Tetrahedron Lett. 1994, 35, 3051. (b) Jeffery, T. Tetrahedron 1996, 52, 10113. (c) de Meijere, A.; Meyer, F. E. Angew. Chem., Int. Ed. Engl. 1994, 33, 2379. (d) Grigg, R. J. Heterocycl. Chem. 1994, 31, 631. (e) Horniakova, J.; Raja, T.; Kubota, Y.; Sugi, Y. J. Mol. Catal. A: Chem. 2004, 217, 73. (f) Bharat Kumar, A.; Krishna Nand, S. Synthesis 2011, 7, 1125.

ACKNOWLEDGMENTS This research work dedicated to Prof. Michael P. Doyle, Department of Chemistry, The University of Texas at San Antonio. Financial support by the Council of Scientific and Industrial Research [(CSIR), No. 02(0262)/16/EMR-II], New Delhi is gratefully acknowledged. KR. thanks MHRD, New Delhi, for the award of a research fellowship. We also thanks Dr. Dattatraya Dethe, IIT Kanpur, for his support.

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