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Cite This: J. Org. Chem. 2017, 82, 11954-11960
Chiral Atropisomeric 8,8′-Diiodobinaphthalene for Asymmetric Dearomatizing Spirolactonizations in Hypervalent Iodine Oxidations Toshifumi Dohi,*,† Hirotaka Sasa,† Keitaro Miyazaki,† Mihoyo Fujitake,‡ Naoko Takenaga,§ and Yasuyuki Kita*,∥ †
College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577, Japan Central Research Laboratories, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan § Department of Chemical Science and Technology, Hosei University, Kajino-cho 3-7-2, Koganei, Tokyo 184-8584, Japan ∥ Research Organization of Science and Technology, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577, Japan ‡
S Supporting Information *
ABSTRACT: A new type of binaphthyl-based chiral iodide functionalized at positions 8 and 8′ of the naphthalene rings has been found as a promising structural motif for the asymmetric hypervalent iodine(III) oxidations, specifically, for the dearomatizing spirocyclization of naphthol carboxylic acids showing expectedly better enantioselectivities versus other atropisomeric biaryls, i.e., a conventionally used binaphthalene having the diiodides in the minor groove.
T
he reagent and catalyst based on the atropisomeric biaryl molecules, especially those having 1,1′-binaphthalene structures, are highly important in synthetic organic chemistry and have played a significant role in the development of new asymmetric transformations. Previously, the chiral, C2-symmetric, 2,2′-difunctionalized binaphthalene molecules were originally employed as ligands for asymmetric transition metal-catalyzed reactions. As represented by the elegant designs of BINOL and BINAP (Figure 1),1 specific chiral environments
The hypervalent iodine reagent is known as a versatile alternative to the toxic heavy metal oxidants such as lead, thallium, and mercury, including inorganic oxidants, and together with the advances in its catalytic uses, and the fact that its safe use and easy handling are consistent with green chemistry, has attracted the attention of synthetic chemists in recent years.3,4 Asymmetric oxidations using these reagents and catalysts are some of the hot topics regarding the developments in the metal-free coupling area for constructing a new chiral carbon center during the organocatalytic bond-forming reaction with enantiocontrol.5,6 The applications of the universal chiral 1,1′-binaphthalene motif have also appeared in hypervalent iodine chemistry, and 1,1′-binaphthyl-2,2′-diiodide (Figure 1, FG = I) and its derivatives in combination with co-oxidants or their corresponding active hypervalent forms were reported to mediate the asymmetric α-arylation of a cyclic β-diketone,7a aziridination of alkenes,7b,c oxidative diamination of styrene,7d dearomatizing spirocyclization of naphthol carboxylic acids,7e and phenol and naphthol dearomatizing reactions.8 Despite the recent successes in the asymmetric λ5-iodane transformations,8 these trials involving the hypervalent iodine(III) oxidations7 seem to still have led to limited development in view of the modern requirement of stereocontrol; the maximum ee value observed in the products was 53% (30% yield)7a for stoichiometric use and only 36% (63% yield)7e as the catalyst.
Figure 1. Representative chiral 1,1′-binaphthyl ligand and catalyst, and their corresponding derivatives.
are created around the reactive catalytic site embedded in the minor groove of the binaphthalene molecules through the coordination of the heteroatoms of the chiral ligand to the metal center (oxygens in BINOL, phosphorus groups in BINAP). The utilities of the chiral 1,1′-binaphthalene motif as the privileged structure of the new asymmetric catalyst continue to further expand by manipulations of the structures and are now beyond the organometallic chemistry and the group 16 elements.2 © 2017 American Chemical Society
Special Issue: Hypervalent Iodine Reagents Received: August 12, 2017 Published: October 6, 2017 11954
DOI: 10.1021/acs.joc.7b02037 J. Org. Chem. 2017, 82, 11954−11960
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The Journal of Organic Chemistry In this study, we first report a set of new chiral binaphthalene compounds having iodide functionalities embedded in the major groove of the naphthalene rings that dramatically improve the enantioselectivity. Hence, the designed new chiral iodides in the hypervalent iodine(III)-induced asymmetric oxidative spirocyclization of naphthol carboxylic acids gave the dearomatized spirolactones in high ee’s versus those of the reported 2,2′-diiodide isomers (Scheme 1).
The spirobiindane catalyst 1 in situ activated the corresponding μ-oxo hypervalent iodine(III) form after treatment with a suitable co-oxidant, i.e., m-chloroperbenzoic acid (mCPBA), and then it can cause the oxidative dearomatization giving the spirocyclized products 5 in high ee’s. Meanwhile, instead of using 2,2′-diiodo-1,1′-binaphthalene 27a for the catalytic systems and transformations with a somewhat disappointing stereoselectivity, the asymmetric spirocyclization of naphthol carboxylic acids 4a (R′ = H) using 2,2′-diiodobinaphthyl 2 (>99% ee) as its hypervalent iodine form was tested; however, product formation with at best a 5% enrichment of the one enantiomer resulted.10,11 Considering the ligand exchange model of substrate 4a at the iodine(III) center of spirobiindane molecule 1, we now alternatively suggest a regioisomeric 1,1′binaphthalene 3a bearing the iodine groups within the major groove of the naphthalene rings as the reagent and catalyst for enabling the suitable construction of the chiral environment similar to spirobiindane catalyst 1 during the oxidative dearomatizing spirolactonizations (eq 1, Scheme 2). Enantiopure 8,8′-diiodo-1,1′-binaphthalene 3a12a was successfully synthesized by Sandmeyer-type iodination of the corresponding diamine without racemization of the axial configuration (Scheme 3). Several types of 8,8′-difunctionalized 1,1′-binaphthelene compounds were reported,12 and the required 8,8′-diamino precursor was readily prepared from 8amino-1-bromonaphthalene by nickel-catalyzed reductive homocoupling according to Tsubaki’s literature procedure,12b which was originally reported for the synthesis of 2,2′-dimethyl8,8′-diiodo-1,1′-binaphthalene. The enantiomeric resolution of the obtained racemic diamine was then performed by preparative HPLC using a chiral stationary phase column.
Scheme 1. New Binaphthalene-Based Hypervalent Iodine Catalysts for Asymmetric Dearomatizing Spirocyclization of Naphthol Carboxylic Acids Producing Spirolactones
A pioneering study in the area of asymmetric hypervalent iodine oxidations has previously been reported for the enantioselective oxidative spirocyclizations of 3-(1-hydroxy-2naphthyl)propionic acids 4 using stoichiometric and catalytic amounts of a chiral hypervalent iodine oxidant and catalyst 1.9
Scheme 2. Structural Comparison of 8,8′-Diiodo-1,1′-binaphthalene 3a with Spirobiindane Diiodide 1 and 2,2′-Diiodo-1,1′binaphthalene 2 and Ligand Exchange Model for the Stereoselective Formation of Spirolactone Products 5a
11955
DOI: 10.1021/acs.joc.7b02037 J. Org. Chem. 2017, 82, 11954−11960
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The Journal of Organic Chemistry Scheme 3. Synthesis of 8,8′-Diiodo-1,1′-binaphthalene 3a and Its 2,2′-Disubstituted Derivatives, 3b and 3c, from the Bromonaphthylamines
and thus, no racemization was observed. On the other hand, a more sterically congested binaphthalene 3c with the isopropyl substituents, compared to o-dimethyl binaphthalene 3b, gave slightly inferior results in terms of the yield and ee value of product 5a (entry 3). For chiral binaphthalene 3b that showed the best yield and ee among those compounds examined, the effects of the concentration were investigated, and the ee value of product 5a substantially decreased as the concentration increased (entries 4 and 5). At the higher concentration (0.2 M), the addition of acetic acid was found to be effective and the reaction achieved almost the same yield and ee that were obtained at the low concentration (compare entries 6 and 2); this is probably because acetic acid can prevent the formation of some insoluble hypervalent iodine(III) oligomers from the reactive monomeric species.14 The product yield was further improved by increasing the amount of diiodide 3b, which reached 91% when 1 equiv of reagent 3b was used relative to substrate 4a (entry 7). Chloroform was better as a solvent than dichloromethane was, and the reactions at both higher and lower temperatures did not lead to an improvement in the yield or ee values. The yield and ee values are compatible with those obtained by the reaction using isolated μ-oxo iodine(III) species 3b′ prepared from catalyst 3b and mCPBA (for details, see the Supporting Information). The generality of the asymmetric inductions with reagent 3b giving the highest ee scores for an extensive series of substrates was confirmed under the optimized reaction conditions of entry 2 in Table 1 for the stoichiometric reactions. The selected examples of ring-substituted 1-naphthol-2-propionic acids 4b−i are shown in Table 2. The reaction system with 8,8′diiodobinaphthyl 3b was found to be optimal for derivatives 4b−i with a substituent at positions 3−6 of the naphthalene rings, and the desired spirolactones 5b−i were produced without a significant loss of the enantioselectivities except for substrate 4e having a 4-methoxy group.15 Thus, product 5b carrying a large phenyl group attached ortho to the creating spirocyclic carbon was formed while the yield and ee values were maintained. Also, 4-chloro substrate 4c was converted into a spirolactone 5c in a good yield with a slightly reduced ee. As we experienced for spirobiindane catalyst 1,9 the presence of some electron-donating groups at the para position of the 1naphthol acids negatively influenced the yield and ee during the reactions (see substrates 4d and 4e). Substrates 4f−h having a bromo, azide, and benzyloxy group at the naphthalene 5 position, respectively, smoothly reacted and provided the corresponding spirolactones 5f−h, respectively, with slight differences in ee values ranging from 64 to 72%. The azide functional group at position 6 of the naphthalene ring of substrate 4i somewhat contributed to the improvement in the ee, which is in sharp contrast to the result for 5-substituted
Optically active diiodide 3a (>99% ee) is a stable, microcrystalline solid and did not cause any detectable racemization at room temperature during storage without protection from light and air. Similarly, 2,2′-disubstituted derivatives 3b and 3c in optically pure forms were synthesized from the corresponding bromonaphthylamines having methyl and isopropyl groups using the aforementioned synthetic schemes and enantiomeric resolutions (for the synthetic details, see the Experimental Section).13 The enantioselective performances of prepared chiral 8,8′diiodo-1,1′-binaphthalenes 3a−c were then examined for the dearomatizing spirocyclization of 1-naphthol-2-propionic acid 4a, a reference substrate, using mCPBA as a co-oxidant (Table 1). During the reactions, 8,8′-diiodobinaphthalenes 3a−c were Table 1. Yields and ee Values in the Oxidative Dearomatizing Cyclization of a Naphthol Carboxylic Acid 4a Leading to Spirolactone 5a Using 8,8′-Diiodobinaphthyl Compounds 3a−c
entry
diiodobinaphthyl (3)
[4a] (M)
1 2 3 4 5 6b 7
(S)-3a (S)-3b (S)-3c (S)-3b (S)-3b (S)-3b (S)-3bc
0.01 0.01 0.01 0.04 0.2 0.2 0.01
yield (%), ee (%)a 51, 70, 50, 70, 66, 68, 91,
50 74 64 72 64 76 74
a
The yields of spirolactone 5a were determined after purification. The ee values were measured by HPLC analysis using a chiral separation column. bOne equivalent of acetic acid was added. cPerformed using 1 equiv of the catalyst.
in situ activated to the hypervalent iodine(III) forms by oxidation of the iodine atoms by mCPBA.14 On the basis of our expectation, even the simplest 8,8′-diiodo-1,1′-binaphthalene 3a showed moderate asymmetric inductions, and the substoichiometric use of (S)-3a (0.55 equiv) in chloroform at −40 °C afforded spirolactone 5a in 51% yield with 50% ee during the reaction of reference substrate 4a (0.01 M) after 2 h (entry 1). Furthermore, binaphthalene 3b bearing the two methyl groups ortho to the biaryl axis produced product 5a with a higher yield of 70% and enantioselectivity of 74% ee (entry 2). Although one might assume that partial racemization might occur in these 8,8′-diiodo-1,1′-binaphthalene molecules, optically pure 3a and 3b were recovered after the reactions, 11956
DOI: 10.1021/acs.joc.7b02037 J. Org. Chem. 2017, 82, 11954−11960
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The Journal of Organic Chemistry
spirolactone 5a in an acceptable yield with a reasonable ee after 2 h. In summary, we have reported a new reagent design for the hypervalent iodine(III)-induced asymmetric dearomatizing spirocyclizations by new types of atropisomeric biaryl molecules 3 bearing the iodine atoms in the major groove of the naphthalene rings. It was found that 8,8′-diiodonaphthalene molecules 3 possess stable atropisomerisms, and 2,2′-dimethyl derivative 3b proposed by the rational design of the ligand exchange model of the previous spirobiindane catalyst 1 especially demonstrated a promising level of asymmetric control up to 78% ee (for substrate 5i).
Table 2. Asymmetric Dearomatizing Spirocyclizations of 1Naphthol-2-propionic Acids 4b−i Using a Stoichiometric Chiral 8,8′-Diiodobinaphthyl Reagent 3ba
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EXPERIMENTAL SECTION
General Remarks. The melting point (mp) was measured by a Stuart SMP3 AC input 100 V melting point apparatus. 1H NMR (and 13 C NMR) spectra were recorded with JEOL JMN-400 or -300 spectrometers operating at 400 or 300 MHz (100 or 75 MHz for 13C NMR) at 25 °C with tetramethylsilane (δ 0.0) as an internal standard. The data are reported as follows: chemical shift in parts per million (δ), integration, multiplicity (s, singlet; d, doublet; t, triplet; m, multiplet), and coupling constant (hertz). Infrared spectra (IR) were obtained using a Hitachi 270-50 spectrometer; absorptions are reported in reciprocal centimeters. High-resolution mass spectra (HRMS) were performed by the Elemental Analysis Section of Osaka University of Pharmaceutical Sciences [JEOL JMS-700(2)]. Analytical thin-layer chromatography (TLC) was performed on MERCK silica gel (grade 60 F254). The spots and bands were detected by UV irradiation (254 or 365 nm) and/or by staining with 5% phosphomolybdic acid followed by heating. Column chromatography for isolation of spirolactone products 5 was performed on Merk silica gel 60 (230−400 mesh). HPLC analyses of the obtained spirolactone products 5 were performed using a JASCO DM-2010 multiwavelength detector. The chiral columns included Chiralcel OD and OD-H and Chiral-pac IA and IB columns (Daicel Chemical Industries, Ltd., 0.46 φ × 25 cm). Naphthol carboxylic acids 4a−i were prepared using the reported methods.9 Unless otherwise noted, all other chemicals for the reactions and chromatography in this study were obtained from commercial suppliers and used as received without further purification. We used commercial water-containing mCPBA (∼69% pure with ∼25% water) as supplied. Preparation of Binaphthalene-Based Hypervalent Iodine Catalyst 3a. Racemic 8,8′-diamino-1,1′-binaphthalene was obtained from 8-bromo-1-naphthylamine using the reported coupling procedure12b as follows. A mixture of activated zinc (48.4 mg, 0.74 mmol), dibromobis(triphenylphosphine)nickel(II) (111.5 mg, 0.15 mmol), and tetraethylammonium iodide (126 mg, 0.49 mmol) in dry tetrahydrofuran (THF, 1 mL) was stirred for 1 h under an argon atmosphere. To the mixture was added 8-bromo-1-naphthylamine (109 mg, 0.49 mmol) in dry THF (1 mL) at room temperature, and the mixture was stirred for 1 h at 50 °C. Aqueous ammonium chloride was added to the mixture, and the organic phase was separated and washed with brine. The aqueous solutions were extracted with ethyl acetate. The combined organic layer was washed with brine, dried over sodium sulfate, and then evaporated in vacuo. The residue was purified by column chromatography on silica gel to give 8,8′-diamino-1,1′binaphthalene (47.3 mg, 0.17 mmol, 68% yield). The enantiomeric resolution of the racemic diamine was achieved by preparative HPLC with a chiral stationary phase column (Daicel Chiralflash IA, n-hexane/ tetrahydrofuran/ethanol/diethylamine eluent, 25 °C, λ = 230 nm). Thus, obtained 8,8′-diamino-1,1′-binaphthalene (50 mg, 0.18 mmol) was suspended in 0.5 mL of water. This suspension was cooled to 0 °C, and then H2SO4 (0.08 mL) was dropped and stirred for 30 min. To this mixture was added acetone (0.8 mL), and the mixture was stirred for 10 min; then NaNO2 (73 mg, 1.06 mmol) in water (0.5 mL) was added, and the mixture was stirred for 30 min at 0 °C. The reaction mixture was added to an aqueous solution of potassium iodide (292 mg, 1.76 mmol, 0.5 mL) and then stirred for 5
a Reactions were performed using 0.55 equiv of chiral reagent (S)-3b, 2 equiv of wet mCPBA as a co-oxidant, with substrates 4b−i in chloroform (0.01 M) at −40 °C unless otherwise noted. All the reactions reached completion within 2 h, and the yields of pure spirolactones 5b−i are indicated. bOne equivalent of chiral reagent (R)-3b was instead used.
substrate 4g. These reactivity trends of substrates 4b−i for 8,8′diiodobinaphthalene reagent 3b were mostly in accord with the results that were previously found for spirobiindane catalyst 1. After the reactions, a large volume of used binaphthalene reagent 3b was recovered in a pure form during column chromatography for isolation of products 5b−i, which were reused for a second run of the asymmetric reactions. With regard to the future molecular design in catalysis4 utilizing this new atropisomeric diiodide skeleton, to ensure the promising catalytic activity of 8,8′-diiodobinaphthalene 3b, we performed the following experiment (Scheme 4). To our delight, the catalytic oxidation of representative substrate 4a with a 10 mol % loading of reagent (R)-3b in combination with 1.3 equiv of the stoichiometric mCPBA co-oxidant still permitted the smooth formation of the target dearomatized Scheme 4. Catalytic Activity of 8,8′-Diiodo-2,2′-dimethyl1,1′-binaphthalene 3b [10 mol % (R)-3b and 1.3 equiv of mCPBA were used]a
a
The original spirobiindane catalyst (S)-1 gave the same product 5a at the maximum 65% ee.9 11957
DOI: 10.1021/acs.joc.7b02037 J. Org. Chem. 2017, 82, 11954−11960
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The Journal of Organic Chemistry h at room temperature. The resulting reaction mixture was extracted with ethyl acetate. The organic phase was washed with 1 M aqueous HCl, dilute aqueous sodium thiosulfate, water, and saturated aqueous NaCl and then dried with anhydrous Na2SO4. After removal of the solvent, the residue was subjected to column chromatography on silica gel to give 8,8′-diiodo-1,1′-binaphthalene 3a (50.3 mg, 0.099 mmol, 55% yield). 8,8′-Diiodo-1,1′-binaphthalene (3a). 12a Obtained as a pale yellow solid: mp 132−138 °C; 1H NMR (400 MHz, CDCl3) δ 7.06− 7.11 (2H, m), 7.30 (2H, dd, J = 1.5, 7.1 Hz), 7.43−7.50 (2H, m), 7.89−7.96 (4H, m), 8.21 (2H, dd, J = 1.2, 7.4 Hz); 13C NMR (100 MHz, CDCl3) δ 93.7, 124.7, 126.5, 129.8, 129.9, 133.1, 133.2, 135.4, 139.4, 142.1; IR (KBr) 3051, 2923, 1553, 1359, 1194, 946, 817, 765, 714 cm−1. Preparation of Dimethyl Binaphthalene Catalyst 3b. The (S)(−)- and (R)-(+)-2,2′-dimethyl[1,1′-binaphthalene]-8,8′-diamines are known compounds and thus were prepared according to the literature.12b The enantiomeric resolution of the racemic diamine was achieved by preparative HPLC with a chiral stationary phase column (Daicel Chiralflash IA, n-hexane/tetrahydrofuran/ethanol/ diethylamine eluent, 25 °C, λ = 230 nm). The optically pure 2,2′dimethyl-binaphthalene diamine (120 mg, 0.38 mmol, >99% ee) was suspended in 1.2 mL of water. This suspension was cooled to 0 °C, and then H2SO4 (0.2 mL) was dropped and stirred for 30 min. To this mixture was added acetone (0.4 mL), and the mixture was stirred for 10 min; then NaNO2 (159 mg, 2.31 mmol) in a small amount of water was added, and the mixture was stirred for 30 min at 0 °C. The reaction mixture was added to a solution of potassium iodide (638 mg, 3.84 mmol) in a small amount of water and then stirred for 5 h at room temperature. The resulting reaction mixture was extracted with ethyl acetate. The organic phase was successively washed with 1 M aqueous HCl, dilute aqueous sodium thiosulfate, water, and saturated aqueous NaCl and then dried with anhydrous Na2SO4. After removal of the solvent, the residue was subjected to column chromatography on silica gel to give a pure 8,8′-diiodo-2,2′-dimethyl-1,1′-binaphthalene 3b (145.8 mg, 71% yield). (S)-(−)-8,8′-Diiodo-2,2′-dimethyl-1,1′-binaphthalene (3b). Obtained as a pale yellow solid: mp 151−159 °C; [α]27D −14.7 (c 0.985, chloroform); 1H NMR (400 MHz, CDCl3) δ 1.74 (6H, s), 6.96−7.02 (2H, m), 7.41 (2H, d, J = 8.3 Hz), 7.81−7.88 (4H, m), 8.19 (2H, dd, J = 7.3, 1.2 Hz); 13C NMR (100 MHz, CDCl3) δ 22.1, 91.8, 125.5, 129.2, 129.5, 130.2, 133.4, 133.7, 135.4, 138.3, 142.7; IR (KBr) 3049, 2916, 1598, 1538, 1499, 1410, 1308, 1218, 1188, 1137, 964, 824, 769, 726, 644 cm−1; HRMS (FAB) calcd for C22H16I2 [M]+ 533.9341, found 533.9340. Preparation of Isopropyl Binaphthalene Catalyst 3c. To nitric acid (35 mL) was added 1-bromo-2-isopropylnaphthalene (22.0 g, 88 mmol) dropwise under ice-bath cooling, and the mixture was stirred for 2 h. After slow addition of an ice/water mixture (110 mL), ether acetate (110 mL) was added under ice-bath cooling. The organic layer was then separated and washed successively with water and saturated brine. After being dried with anhydrous Na2SO4, the solvent was evaporated in vacuo. The residue was purified by column chromatography to successively afford 1-bromo-2-isopropyl-8-nitronaphthalene (7.0 g, 23.8 mmol, 27%) as a yellow solid, which was used for further transformation. A mixture of the obtained 1-bromo-2-isopropyl-8-nitronaphthalene (7.04 g, 23.9 mmol) and SnCl·2H2O (54 g, 239 mmol) in ethyl acetate (340 mL) was stirred under reflux conditions for 24 h. After the mixture had cooled, the reaction was quenched with aqueous NaOH and aqueous sodium hydrogen carbonate, and the resulting solution was filtered through Celite. After the mixture had been dried with anhydrous Na2SO4, the solvent was evaporated and the residue was subjected to column chromatography on silica gel to give 8-bromo-7isopropylnaphthalen-1-amine (4.27 g, 16.2 mmol, 68% yield) as a pale purple solid. A mixture of activated zinc (1.67 g, 25.5 mmol), dibromobis(triphenylphosphine)nickel(II) (3.6 g, 4.85 mmol), and tetraethylammonium iodide (4.16 g, 16.2 mmol) in dry tetrahydrofuran (THF, 20 mL) was stirred for 1 h under an argon atmosphere. To the mixture
was added 8-bromo-7-isopropylnaphthalen-1-amine (4.27 g, 16.2 mmol) in dry THF (20 mL) at room temperature, and the mixture was stirred for 1 h at 50 °C. Aqueous ammonium chloride was added to the mixture, and the organic phase was separated and washed with brine. The aqueous solutions were extracted with ethyl acetate. The combined organic layer was washed with brine, dried over sodium sulfate, and then evaporated in vacuo. The residue was purified by column chromatography on silica gel to give 2,2′-diisopropyl[1,1′binaphthalene]-8,8′-diamine (1.98 g, 5.4 mmol, 67% yield) as a pale purple solid. Enantiomeric resolution of the racemic diamine was achieved by preparative HPLC with a chiral stationary phase column (Daicel Chiralflash IA, n-hexane/ethyl aceate eluent, 25 °C, λ = 230 nm). The thus obtained enantiopure 2,2′-diisopropyl[1,1′-binaphthalene]-8,8′-diamine (50.0 mg, 0.14 mmol) was suspended in 0.4 mL of water. This suspension was cooled to 0 °C, and then H2SO4 (0.06 mL) was dropped and stirred for 30 min. To this mixture was added acetone (0.6 mL), and the mixture was stirred for 10 min; then NaNO2 (57 mg, 0.82 mmol) in water (0.4 mL) was added, and the mixture was stirred for 30 min at 0 °C. The reaction mixture was added to an aqueous solution of potassium iodide (232 mg, 1.4 mmol, 0.4 mL) and then the mixture stirred for 5 h at room temperature. The resulting reaction mixture was extracted with ethyl acetate. The organic phase was washed with 1 M aqueous HCl, dilute aqueous sodium thiosulfate, water, and saturated aqueous NaCl and then dried with anhydrous Na2SO4. After removal of the solvent, the residue was subjected to column chromatography on silica gel to give binaphthalene diiodide 3c, 8,8′-diiodo-2,2′-diisopropyl-1,1′-binaphthalene (42.5 mg, 0.072 mmol, 51% yield). 8,8′-Diiodo-2,2′-diisopropyl-1,1′-binaphthalene (3c). Obtained as a pale yellow solid: mp 90−91 °C; 1H NMR (400 MHz, CDCl3) δ 0.94 (6H, d, J = 6.8 Hz), 1.04 (6H, d, J = 6.8 Hz), 2.10−2.16 (2H, m), 6.97−7.02 (2H, m), 7.53 (2H, d, J = 9.0 Hz), 7.83−7.92 (4H, m), 8.21 (2H, d, J = 6.6 Hz); 13C NMR (100 MHz, CDCl3) δ 23.0, 24.1, 30.7, 94.6, 124.5, 125.7, 129.9, 130.1, 132.8, 133.5, 134.4, 142.9, 147.9; IR (KBr) 3052, 2964, 2867, 1605, 1537, 1502, 1459, 1419, 1383, 1362, 1297, 1241, 1192, 1142, 1070, 1044, 964, 910, 827, 736, 673, 648 cm−1; HRMS (FAB) calcd for C26H24I2 [M]+ 589.9967, found 589.9990. Typical Procedure for the Dearomatizing Spirolactonization by an ortho-Substituted Iodoarene Catalyst 3b. To a stirred solution of (S)-3b (29.3 mg, 0.055 mmol) in chloroform (10 mL) was added the wet m-chloroperbenzoic acid (mCPBA, ∼69% pure, including ∼25% water, 50 mg, 0.2 mmol) at room temperature. The mixture was stirred for 15 min and then cooled to −40 °C. Naphtholcarboxylic acid 4a (21.6 mg, 0.10 mmol) was added to the mixture, while the progress of the reaction was monitored by TLC. After the reaction was completed, saturated aqueous NaHCO3 was added to the mixture. The organic layer was separated, and the aqueous phase was extracted with dichloromethane several times. The combined organic extract was dried over anhydrous Na2SO4 and evaporated to dryness. The residue was purified by silica gel chromatography to give (R)-5a (15.0 mg, 0.070 mmol) in 70% yield. (R)-(+)-1′H,3H-Spiro[furan-2,2′-naphthalene]-1′,5(4H)-dione (5a).9a Obtained as a white powder: mp 104−105 °C; 1H NMR (300 MHz, CDCl3) δ 2.13−2.25 (1H, m), 2.39−2.47 (1H, m), 2.55−2.65 (1H, m), 2.85−2.98 (m, 1H), 6.21 (1H, d, J = 9.9 Hz), 6.66 (1H, d, J = 9.9 Hz), 7.26 (1H, d, J = 7.2 Hz), 7.41 (1H, t, J = 7.5 Hz), 7.64 (1H, t, J = 7.5 Hz), 8.02 (1H, d, J = 7.8 Hz); 13C NMR (75 MHz, CDCl3) δ 26.4, 31.0, 83.4, 127.1, 127.5, 127.8, 127.9, 128.8, 132.1, 135.6, 136.7, 176.5, 196.5. The ee value of obtained product 5a was determined by HPLC (OD-H chiral column, n-hexane/isopropanol eluent, 25 °C, λ = 230 nm). The use of the (R) enantiomer of catalyst 3b under the same procedure could preferentially afford the product of opposite enantiomer (S)-5a in almost the same yield and ee value. For the separation columns for other spirolactones 5b−i, see the Supporting Information, and the physical and spectral data of 5b−i matched well those of the authentic sample.9 11958
DOI: 10.1021/acs.joc.7b02037 J. Org. Chem. 2017, 82, 11954−11960
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The Journal of Organic Chemistry (R)-(+)-3′-Phenyl-1′H,3H-spiro[furan-2,2′-naphthalene]1′,5(4H)-dione (5b). Obtained as a white powder: mp 172−173 °C; 1 H NMR (300 MHz, CDCl3) δ 2.19−2.22 (1H, m), 2.38−2.42 (2H, m), 2.76−2.83 (1H, m), 6.69 (1H, s), 7.31 (1H, d, J = 7.2 Hz), 7.39− 7.46 (4H, m), 7.50−7.52 (2H, m), 7.65 (1H, t, J = 6.2 Hz), 8.06 (1H, d, J = 6.8 Hz); 13C NMR (75 MHz, CDCl3) δ 26.4, 30.6, 85.4, 126.4, 127.3, 127.9, 128.3, 128.6, 128.7, 128.8, 129.2, 135.8, 136.6, 137.2, 176.5, 196.5. (R)-(+)-4′-Chloro-1′H,3H-spiro[furan-2,2′-naphthalene]1′,5(4H)-dione (5c). Obtained as a white powder: mp 98−107 °C; 1 H NMR (400 MHz, CDCl3) δ 2.16−2.27 (1H, m), 2.40−2.48 (1H, m), 2.55−2.65 (1H, m), 2.83−2.95 (1H, m), 6.38 (1H, s), 7.23−7.53 (1H, m), 7.70−7.78 (2H, m), 8.03−8.07 (1H, m); 13C NMR (100 MHz, CDCl3) δ 26.5, 31.4, 126.1, 127.3, 127.3, 128.1, 129.1, 130.1, 131.8, 134.5, 135.8, 175.8, 194.7. (R)-(+)-4′-Ethyl-1′H,3H-spiro[furan-2,2′-naphthalene]1′,5(4H)-dione (5d). Obtained as a white powder: mp 96−97 °C; 1H NMR (300 MHz, CDCl3) δ 1.26 (3H, t, J = 7.2 Hz), 2.13−2.22 (1H, m), 2.36−2.45 (1H, m), 2.54−2.64 (3H, m), 2.82−2.96 (1H, m), 6.00 (1H, s), 7.42 (1H, t, J = 7.5 Hz), 7.46 (1H, d, J = 8.1 Hz), 7.68 (1H, dd, J = 7.8 Hz, 1.5 Hz), 8.05 (1H, dd, J = 7.8 Hz, 1.5 Hz); 13C NMR (75 MHz, CDCl3) δ 12.2, 24.8, 26.7, 31.4, 83.7, 124.2, 127.0, 127.3, 127.8, 128.4, 135.4, 137.3, 138.1, 176.5, 196.8. (±)-4′-Methoxy-1′H,3H-spiro[furan-2,2′-naphthalene]1′,5(4H)-dione (5e). Obtained as a slightly yellow oil: 1H NMR (300 MHz, CDCl3) δ 2.14−2.25 (1H, m), 2.45−2.53 (1H, m), 2.57−2.67 (1H, m), 2.90−3.03 (1H, m), 3.85 (3H, s), 5.12 (1H, s), 7.47 (1H, t, J = 7.8 Hz), 7.68 (1H, t, J = 7.2 Hz), 7.76 (1H, d, J = 7.2 H,), 8.01 (1H, d, J = 7.8 Hz); 13C NMR (75 MHz, CDCl3) δ 27.7, 33.1, 55.3, 83.9, 100.0, 123.2, 127.2, 127.5, 129.4, 134.6, 125.3, 152.0, 176.6, 195.7. (R)-(+)-5′-Bromo-1′H,3H-spiro[furan-2,2′-naphthalene]1′,5(4H)-dione (5f). Obtained as a slightly yellow solid: mp 108−109 °C; 1H NMR (400 MHz, CDCl3) δ 2.14−2.23 (1H, m), 2.36−2.42 (1H, m), 2.55−2.62 (1H, m), 2.80−2.89 (1H, m), 6.31 (1H, d, J = 10.2 Hz), 7.08 (1H, d, J = 10.3 Hz), 7.22−7.28 (1H, m), 7.82 (1H, dd, J = 7.1, 1.0 Hz,), 7.95 (1H, d, J = 7.1 Hz); 13C NMR (100 MHz, CDCl3) δ 26.3, 31.1, 82.8, 122.7, 126.3, 127.1, 129.0, 129.9, 133.7, 135.6, 139.6, 176.1, 195.8. (R)-(+)-5′-Azido-1′H,3H-spiro[furan-2,2′-naphthalene]1′,5(4H)-dione (5g). Obtained as a slightly yellow solid: mp 144− 146 °C; 1H NMR (400 MHz, CDCl3) δ 2.11−2.20 (1H, m), 2.34− 2.40 (1H, m), 2.53−2.60 (1H, m), 2.79−2.89 (1H, m), 6.19 (1H, d, J = 10.2 Hz), 6.93 (1H, d, J = 10.2 Hz), 7.37−7.44 (2H, m), 7.76 (1H, t, J = 7.4 Hz); 13C NMR (100 MHz, CDCl3) δ 26.3, 31.2, 83.2, 121.9, 123.9, 124.7, 127.9, 128.6, 129.7, 132.3, 136.9, 176.2, 196.1. (R)-(+)-5′-(Benzyloxy)-1′H,3H-spiro[furan-2,2′-naphthalene]1′,5(4H)-dione (5h). Obtained as a pale yellow solid: mp 192−194 °C; 1H NMR (400 MHz, CDCl3) δ 2.17−2.23 (1H, m), 2.40−2.46 (1H, m), 2.56−2.63 (1H, m), 2.84−2.94 (1H, m), 5.16 (2H, s), 6.18 (1H, d, J = 10.2 Hz), 7.16−7.28 (2H, m), 7.33−7.45 (6H, m), 7.64 (1H, d, J = 7.8 Hz); 13C NMR (100 MHz, CDCl3) δ 26.5, 31.2, 70.8, 83.6, 118.8, 119.8, 121.8, 126.1, 127.4, 128.3, 128.7, 129.6, 131.0, 136.0, 154.3, 176.5, 196.9. (S)-(−)-6′-Azido-1′H,3H-spiro[furan-2,2′-naphthalene]1′,5(4H)-dione (5i). Obtained as a white powder: mp 127−128 °C; 1 H NMR (400 MHz, CDCl3) δ 2.16−2.20 (1H, m), 2.38−2.44 (1H, m), 2.57−2.64 (1H, m), 2.88−2.98 (1H, m), 6.23 (1H, d, J = 10.0 Hz), 6.61 (1H, d, J = 10.0 Hz), 6.86 (1H, d, J = 2.4 Hz), 7.04 (1H, dd, J = 10.0, 2.4 Hz), 8.03 (1H, d, J = 8.4 Hz); 13C NMR (75 MHz, CDCl3) δ 26.6, 31.5, 82.9, 117.9, 119.1, 123.9, 127.2, 130.1, 134.0, 138.7, 147.7, 176.4, 194.8. Dearomatizing Spirolactonization Using a Catalytic Amount of a New Iodoarene Catalyst 3b (Scheme 4). To a stirred solution of (R)-3b (10.6 mg, 0.020 mmol) in chloroform (20 mL) was added wet mCPBA (∼69% pure, including ∼25% water, 65 mg, 0.26 mmol) at room temperature. The mixture was cooled to −40 °C, and naphtholcarboxylic acid 4a (43.2 mg, 0.20 mmol) was added; the reaction progress was monitored by TLC. After the mixture had been stirred for 2 h, saturated aqueous NaHCO3 was added to the mixture. The organic layer was separated, and the aqueous phase was extracted
several times with dichloromethane. The combined organic extract was dried over anhydrous Na2SO4 and evaporated to dryness. The residue was purified by silica gel chromatography to give (S)-5a (26.6 mg, 0.124 mmol) in 62% yield with 64% ee. We confirmed that the reaction using 1 mmol of substrate 4a in the presence of 10 mol % catalyst (R)-3b gave almost the same results in terms of the product yield and ee value.
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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.7b02037. Copies of NMR spectra of the chiral atropisomeric 8,8′diiodobinaphthalenes 3a−c and HPLC charts for determining the ee values of the spirolactone reaction products 5 (PDF)
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AUTHOR INFORMATION
Corresponding Authors
*E-mail:
[email protected]. *E-mail:
[email protected]. ORCID
Toshifumi Dohi: 0000-0002-2812-9581 Yasuyuki Kita: 0000-0002-2482-0551 Present Address
N.T.: Faculty of Pharmacy, Meijo University, 150 Yagotoyama, Tempaku-ku, Nagoya 468-8503, Japan. Notes
The authors declare no competing financial interest.
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ACKNOWLEDGMENTS This work was supported by a Grant-in-Aid for Scientific Research (A) to Y.K. and a Grant-in-Aid for Encouragement of Young Scientists (A) and Scientific Research (C) to T.D. from JSPS. N.T. also acknowledges a Grant-in-Aid for Encouragement of Young Scientists (B). T.D. thanks the research fund of the Asahi Glass Foundation.
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REFERENCES
(1) (a) Noyori, R. Angew. Chem., Int. Ed. 2002, 41, 2008. (Nobel Lecture) (b) Noyori, R.; Takaya, H. Acc. Chem. Res. 1990, 23, 345. (c) Noyori, R. Homogeneous Asymmetric Hydrogenation. In Asymmetric Catalysis in Organic Synthesis; Wiley: New York, 1994; pp 1−15. (d) Brunel, J. M. Chem. Rev. 2005, 105, 857. (2) For selected reviews, see: (a) Kočovský, P.; Vyskočil, Š.; Smrčina, M. Chem. Rev. 2003, 103, 3213. (b) Telfer, S. G.; Kuroda, R. Coord. Chem. Rev. 2003, 242, 33. (c) Maruoka, K.; Ooi, T.; Kano, T. Chem. Commun. 2007, 1487. (d) Kano, T.; Maruoka, K. Chem. Commun. 2008, 5465. (e) Terada, M. Chem. Commun. 2008, 4097. (f) Schenker, S.; Zamfir, A.; Freund, M.; Tsogoeva, S. B. Eur. J. Org. Chem. 2011, 2011, 2209. (3) For recent reviews; see: (a) Silva, L. F., Jr.; Olofsson, B. Nat. Prod. Rep. 2011, 28, 1722. (b) Yusubov, M. S.; Zhdankin, V. V. Curr. Org. Synth. 2012, 9, 247. (c) Yoshimura, A.; Zhdankin, V. V. Chem. Rev. 2016, 116, 3328. (d) Wirth, T., Ed. Hypervalent Iodine ChemistryModern Developments in Organic Synthesis; Springer-Verlag: Berlin, 2016. (4) For reviews of the catalytic use of a hypervalent iodine reagent, see: (a) Richardson, R. D.; Wirth, T. Angew. Chem., Int. Ed. 2006, 45, 4402. (b) Ochiai, M.; Miyamoto, K. Eur. J. Org. Chem. 2008, 2008, 4229. (c) Dohi, T.; Kita, Y. Chem. Commun. 2009, 2073. (d) Yusubov, M. S.; Zhdankin, V. V. Mendeleev Commun. 2010, 20, 185. (5) For reviews and highlights dealing with asymmetric reactions using chiral hypervalent iodine reagents, see: (a) Berthiol, F. Synthesis 11959
DOI: 10.1021/acs.joc.7b02037 J. Org. Chem. 2017, 82, 11954−11960
Note
The Journal of Organic Chemistry 2015, 47, 587. (b) Parra, A.; Reboredo, S. Chem. - Eur. J. 2013, 19, 17244. (c) Liang, H.; Ciufolini, M. A. Angew. Chem., Int. Ed. 2011, 50, 11849. (d) Ngatimin, M.; Lupton, D. W. Aust. J. Chem. 2010, 63, 653. (6) Recent studies: (a) Mũniz, K.; Barreiro, L.; Romero, R. M.; Martinez, C. J. Am. Chem. Soc. 2017, 139, 4354. (b) Uyanik, M.; Sasakura, N.; Mizuno, M.; Ishihara, K. ACS Catal. 2017, 7, 872. (c) Gelis, C.; Dumoulin, A.; Bekkaye, M.; Neuville, L.; Masson, G. Org. Lett. 2017, 19, 278. (d) Cao, Y.; Zhang, X.; Lin, G.; ZhangNegrerie, D.; Du, Y. Org. Lett. 2016, 18, 5580. (e) Zhu, G.; Bao, G.; Li, Y.; Yang, J.; Sun, W.; Li, J.; Hong, L.; Wang, R. Org. Lett. 2016, 18, 5288. (7) (a) Ochiai, M.; Kitagawa, Y.; Takayama, N.; Takaoka, Y.; Shiro, M. J. Am. Chem. Soc. 1999, 121, 9233. (b) Altermann, S. M.; Richardson, R. D.; Page, T. K.; Schmidt, R. K.; Holland, E.; Mohammed, U.; Paradine, S. M.; French, A. N.; Richter, C.; Bahar, A. M.; Witulski, B.; Wirth, T. Eur. J. Org. Chem. 2008, 2008, 5315. (c) Deng, Q.-H.; Wang, J.-C.; Xu, Z.-J.; Zhou, C.-Y.; Che, C.-M. Synthesis 2011, 2011, 2959. (d) Roben, C.; Souto, J. A.; EscuderoAdan, E. C.; Mũniz, K. Org. Lett. 2013, 15, 1008. (e) Bekkaye, M.; Masson, G. Synthesis 2016, 48, 302. (8) (a) Quideau, S.; Lyvinec, G.; Marguerit, M.; Bathany, K.; Ozanne- Beaudenon, A.; Buffeteau, T.; Cavagnat, D.; Chénedé, A. Angew. Chem., Int. Ed. 2009, 48, 4605. (b) Bosset, C.; Coffinier, R.; Peixoto, P. A.; El Assal, M.; Miqueu, K.; Sotiropoulos, J.-M.; Póuysegu, L.; Quideau, S. Angew. Chem., Int. Ed. 2014, 53, 9860. (9) (a) Dohi, T.; Maruyama, A.; Takenaga, N.; Senami, K.; Minamitsuji, Y.; Fujioka, H.; Cämmerer, S. B.; Kita, Y. Angew. Chem., Int. Ed. 2008, 47, 3787. (b) Dohi, T.; Takenaga, N.; Nakae, T.; Toyoda, Y.; Yamasaki, M.; Shiro, M.; Fujioka, H.; Maruyama, A.; Kita, Y. J. Am. Chem. Soc. 2013, 135, 4558. (10) Recently, we have reported 2,2′-diiodobiphenyl compounds as the efficient precursors of the reactive μ-oxo hypervalent iodine(III) species: (a) Dohi, T.; Takenaga, N.; Fukushima, K.; Uchiyama, T.; Kato, D.; Motoo, S.; Fujioka, H.; Kita, Y. Chem. Commun. 2010, 46, 7697. (b) Dohi, T.; Nakae, T.; Ishikado, Y.; Kato, D.; Kita, Y. Org. Biomol. Chem. 2011, 9, 6899. In the same transformation, the reaction using an optically pure chiral 2,2′-diiodo-4,4′,6,6′-tetramethylbiphenyl in the presence of mCPBA under various conditions produced spirolactone 5a (R′ = H) with poor enantioselectivities (≤7%). (11) For other chiral hypervalent iodine catalysts in the oxidative dearomatizing spirocyclizations, see ref 7e and the following: (a) Uyanik, M.; Yasui, T.; Ishihara, K. Angew. Chem., Int. Ed. 2010, 49, 2175. (b) Uyanik, M.; Yasui, T.; Ishihara, K. Angew. Chem., Int. Ed. 2013, 52, 9215. (c) Murray, S. J.; Ibrahim, H. Chem. Commun. 2015, 51, 2376. (12) (a) Dyker, G. J. Org. Chem. 1993, 58, 234. (b) Tsubaki, K.; Hai, D. T. T.; Reddy, V. K.; Ohnishi, H.; Fuji, K.; Kawabata, T. Tetrahedron: Asymmetry 2007, 18, 1017. (c) Kolotuchin, S. V.; Meyers, A. I. J. Org. Chem. 1999, 64, 7921. (d) Müller, P.; Nury, P.; Bernardinelli, G. Helv. Chim. Acta 2000, 83, 843. (e) Fuji, K.; Ohnishi, H.; Moriyama, S.; Tanaka, K.; Kawabata, T.; Tsubaki, K. Synlett 2000, 351. (13) The optical resolution of the chiral 2,2′-dimethyl-1,1′binaphthyl-8,8′-diamine are possible by diastereomeric resolution after its derivation to the monomenthylcarbamate. See ref 12b. (14) We expect that reactive catalytic species are some oxo hypervalent iodine(III) compounds, such as μ-oxo-bridged hypervalent iodine(III), including mCPBA. See refs 7a, 9, and 10. (15) This strong electronic influence of the 4-methoxy group during the reactions was rationalized by considering the dissociative pathway of the reagent and substrate 4e as well as the rapid formation of the stabilized phenoxenium ion. See ref 9a.
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