Room-Temperature CuI-Catalyzed Amination of Aryl Iodides and Aryl

Publication Date (Web): April 24, 2017. Copyright © 2017 ... *E-mail: [email protected]., *E-mail: [email protected]. Cite this:J. Org. ...
4 downloads 0 Views 880KB Size
Download PDF
Note pubs.acs.org/joc

Room-Temperature CuI-Catalyzed Amination of Aryl Iodides and Aryl Bromides Xiaomei Ding,† Manna Huang,† Zhou Yi,† Dongchen Du,‡ Xinhai Zhu,*,† and Yiqian Wan*,† †

School of Chemical Engineering and Technology and ‡School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, P. R. China S Supporting Information *

ABSTRACT: A general and effective CuI/N′,N′-diaryl-1H-pyrrole-2-carbohydrazide catalyst system was developed for the amination of aryl iodides and bromides at room temperature with good chemoselectivity between −OH and −NH2 groups. Only 5 mol % of CuI and ligands was needed in this protocol to effect the amination of various aryl bromides and aryl iodides with a wide range of aliphatic and aryl amines (1.3 equiv).

T

iodides reacted with aliphatic amines with the great advantage of a high tolerance of a number of reactive functional groups, including −Br and aromatic −NH2 groups as well as phenolic and aliphatic −OH groups.7 However, some disadvantages remained with the need of 20 mol % of supporting ligands and the limitation of substrates to the aliphatic amines.7 Shortly thereafter, Fu’s group reported that 20 mol % of CuBr/1,1′-bi2-naphthol catalyzed the N-arylation of aliphatic amines at room temperature with high selectivity and good functional group tolerance.8 However, electron-rich aryl iodides afforded slightly lower reaction yields, although they could provide higher reactivity when the temperature was increased to 40 (for an Me substituent) or 50 °C (for an OMe substituent).8 In 2010, Tao et al.9 reported that copper(I) iodide (10 mol %)/3acetylcoumarin (20 mol %) could catalyze the N-arylation of aliphatic primary amines and imidazole at room temperature. In 2015, Yao and co-workers10 found that CuI (10 mol %)/N-(1oxy-2-picolyl)oxalamic acid (20 mol %) could effect the amination of aryl halides with aliphatic amines or ammonia at 25 °C under a nitrogen atmosphere in a mixture of DMSO and H2O. In 2016, Evano et al. achieved CuI (20 mol %)/proline (40 mol %)-catalyzed N-arylation of aliphatic amines in DMSO without the need of purification by column chromatography for most products.11 Notably, Liu’s group has developed a series of novel organic phosphorus-containing ionic bases to carry out Cu-catalyzed C−N couplings of aryl iodides and even bromides at room temperature.12 They suggested that the reason for the good performance of such organic bases for C−N coupling is their different ionization abilities, which were determined with the aid of conductivity measurements.12 Furthermore, the disadvantages resulting from the expensive and fairly hygroscopic

he N-arylation of amines for the preparation of anilines has attracted considerable attention for over a century because of the critical role of anilines in academia and in industry and the ubiquitous presence of anilines as highly valuable moieties in numerous natural products, medicinally relevant compounds, agrochemicals, and organic materials in our modern society.1 One of the most attractive and direct approaches for the preparation of anilines is the coppermediated coupling of aryl halides with amines due to the lower cost of copper compared to other precious metals and the lack of using toxic phosphane-containing ligands. However, the need for harsh conditions (e.g., strong bases, stoichiometric copper, high reaction temperatures) limited the application of this reaction until the 2000s.2 Since then, several breakthroughs have overcome most of these drawbacks3 and have greatly extended the reaction scope, in particular, to nonactivated aryl chlorides.4 These breakthroughs have led to numerous practical approaches to synthesizing anilines in both academic and industrial settings. However, further endeavors are still required to make this class of reactions more attractive and practical because of its limitations in comparison to the Buchwald−Hartwig reaction, which include (1) less expensive aryl chlorides still being poor substrates for Cu/ligand-catalyzed aryl amination reactions4a and (2) turnover numbers and turnover frequencies being low at low temperatures in the general catalytic version of the Ullmann reaction (25−80 °C).2b,5 To improve the selectivity of the reaction and save energy as well, allowing transformations to be carried out at ambient temperature is often effective.6 Hence, the development of room-temperature Ullmann-type C−N coupling reaction protocols has also been an emerging and progressing field, as shown here. In 2006, Shafir and Buchwald reported the first highly selective room-temperature copper-catalyzed C−N coupling reactions in which a wide range of aryl and heteroaryl © 2017 American Chemical Society

Received: February 6, 2017 Published: April 24, 2017 5416

DOI: 10.1021/acs.joc.7b00290 J. Org. Chem. 2017, 82, 5416−5423

Note

The Journal of Organic Chemistry

with aniline in water as the model reaction indicated L1 was very effective at promoting the Ullmann-type C−N coupling because the model reaction was complete within 5 min under the catalysis of 5 mol % of CuI and L1 at 120 °C, affording the desired product in 95% isolated yield. Encouraged by this result, we thus wished to investigate the room-temperature Cucatalyzed amination of aryl halides. After opimization through exploration of the copper sources, bases, and solvents as well as different ratios of substrates, catalysts, and ligands, the model reaction of 4-iodoanisole with aniline occurred smoothly under the catalysis of 5 mol % of CuI and L1 in diethylene glycol (DEG) at room temperature (Table S1). Subsequently, a wide range of aryl iodides were aminated with amines under the optimized conditions to explore the scope of this catalyst system. As shown in Table 1, the direct

organic ionic bases could be alleviated by covalently binding phosphonium cations to hydrophobic polymers. The resultant resin-bound organic base was easily recycled and reused.13 Notably, carrying out successfully the coupling of (E)-1-(2bromophenyl)ethanone oximes with aniline under catalysis of only parts-per-million (ppm) levels of CuCl2 at room temperature was key to prevention of high catalyst loadings for Cu-catalyzed C−N couplings at low temperature with obvious substrate limitations to only specific types of oximes.5 In the search for effective ligands for general Cu-catalyzed coupling reactions, we found that CuO/oxalyl dihydrazide/ hexane-2,5-dione effected the reaction of 4-bromoanisole with aniline in 96 h to afford 86% isolated yield of the desired product.14 However, we were perplexed by the high catalyst loading (20 mol %) and ligand consumption (50 mol % oxalyl dihydrazide and 100 mol % hexane-2,5-dione) in the reaction. This substantial limitation has partially been surmounted by the development of a series of ligands.15 For example, only 5 mol % loading of CuAc2/N-methoxy-1H-pyrrole-2-carboxamide was sufficient for effecting typical Ullmann-type C−N coupling,15a although none of the ligands developed could perform this type of reaction at room temperature. To elucidate why large amounts of ligand were required in most of the previously reported cases, we investigated in detail the stability of our previously reported typical ligand, N′phenyl-1H-pyrrole-2-carbohydrazide. We found that the N′phenyl-1H-pyrrole-2-carbohydrazide (A) ligand actually underwent partial transformation to afford at least three compounds (Scheme 1). Significant exploration confirmed that

Table 1. Direct Amination of Aryl Halides with Aminesa

Scheme 1. Transformation of Compound A in Water

(phenyldiazenyl)(1H-pyrrol-2-yl)methanone (B) and N,N′,N′-triphenyl-1H-pyrrole-2-carbohydrazide (C) were inactive under our C−N coupling experimental conditions after their structures were identified by spectral methods and singlecrystal X-ray diffraction technique. Furthermore, this transformation occurred even more rapidly in organic media at room temperature. These results partially accounted for the need of the high loading of our previously reported 1H-pyrrole-2-carbohydrazide ligands and for the poor reactivity in organic media. After identifying the catalytic efficiency of purified L1 and its structure to be N′,N′-diphenyl1H-pyrrole-2-carbohydrazide, we successfully designed and synthesized a series of ligand candidates (Scheme 2). Subsequent optimization using the reaction of 4-bromoanisole

a

Reaction conditions: aryl halide (1 mmol), amine (1.3 mmol), CuI (0.05 mmol), Ligand (0.05 mmol), K3PO4 (2 mmol), diethylene glycol (2 mL): (a) ArI, L1, rt, 12 h; (b) ArI, L1, 50 °C, 1 h; (c) ArBr, L1, 4 Å MS (100 mg), rt, 6 d; (d) ArBr, L1, 60 °C, 3 h; (e) ArI, L1, rt,15 h; (f) ArI, L2, rt, 15 h; (g) ArBr, L1, 4 Å MS (100 mg), rt, 6.5 d; (h) ArBr, L2, 4 Å MS (100 mg), rt, 6.5 d; (i) ArBr, L2, 60 °C, 3 h; (j) ArI, ligand free, rt, 12 h.

Scheme 2. Synthesis and Structures of the Ligands amination of unactivated and nonactivated aryl iodides readily provided the desired products in high yields, and most of the amines functioned well in the reaction regardless of whether they were aromatic or aliphatic amines. Even the bulky adamantyl (1h, 3h, 4h) and acyclic secondary amines (1r, 1s, 4s, 8s, 12s), which were previously considered difficult substrates for this type of reaction,16 afforded the desired products in very good yield. Notably, highly selective N5417

DOI: 10.1021/acs.joc.7b00290 J. Org. Chem. 2017, 82, 5416−5423

Note

The Journal of Organic Chemistry

MS, afforded 75% isolated yield of the product, which demonstrated that the 4 Å MS acted only as a desiccant in the reaction (Table S2). Consequently, the amination of various aryl bromides was run in DEG with activated 4 Å MS (100 mg/2 mL) for the purpose of operational convenience, as shown in Table 1. The performance of the direct amination of aryl bromides with various amines was reminiscent of their aryl iodide counterparts in most cases, requiring only a prolongation of the reaction times. Interestingly, elevating the reaction temperature to 60 °C clearly made the amination of all tested aryl bromides complete within 3 h in 75−91% isolated yields without 4 Å MS. It is well known that aryl chlorides were believed to be unactivated substrates for the Ullmann type C−N coupling. We tried amination of chlorobenzene with aniline using L1 as ligand at room temperature, but the reaction unfortunately did not work. To examine the practical application of the room-temperature C−N coupling protocol, we carried out the synthesis of phenothiazine, which has been demonstrated to play an important role in both human medicine and materials science. As expected, phenothiazine was obtained readily either in two steps in 58% total yield at room temperature or in one pot in 70% yield at 90 °C (Scheme 4).

arylation of amino alcohols (1o−q, 3p, 8p) and amino phenols (1c) further broadened the application scope of the protocol. It should be noted that raising the reaction temperature to 50 °C largely shortened the reaction time to 1 h with the same outcome as that at room temperature (Table 1, 1a, 3a, 4a, 8a, 9a, 12a, 1g, 1l, 1n, 1o, 1s). Intriguingly, 4-nitrophenyl iodide, usually considered an activated substrate,4a poorly participated in this transformation, with a slow rate of initiation and an extended time required for completion. We therefore envisioned that the nitro group would impede the formation of a key rate-determining copper complex. Hence, considering the fact that either p-OMe-ph (L4) or p-NO2-ph (L5) replacing phenyl group of the ligand NAr substituent provided less catalytic efficiency, we modified L1 to afford L2 and make the ligand more bulky. As expected, L2 was found to adequately promote the N-arylation of 4nitrophenyl iodide, providing the desired product in 73% isolated yield, probably as compensation for the electrondonating effect of the isopropyl group and the steric hindrance. From this point on, given the efficiency of the N-arylation of bulky amines, we speculated that the amine coordination to Cu(I) might be the rate-determining step in Cu(I)/Cu(III) catalytic cycles17 under the experimental conditions. Addition of 1.0 equiv of TEMPO did not kill the model reaction (Scheme S1). When an additional radical clock experiment18 was carried out as shown in Scheme 3, the

Scheme 4. Synthesis of Phenothiazine

Scheme 3. Radical Clock Experiment

product from C−N coupling was isolated in 83% yield. These results revealed preliminarily that the reaction proceeded via an ionic rather than a radical pathway under the experimental conditions. It is rarely documented that the room-temperature coppercatalyzed N-arylation of arylamines with aryl bromides that were believed to be either difficult to react with or unreactive toward traditional alkaline bases. Liu’s group accomplished the N-arylation of bromobenzene with aliphtic amines with the 10 mol % CuI/20 mol % ligand system at room temperature using organic ionic bases replacing traditional alkaline bases by taking advantage of the concept of ionization ability.12,13 With the success of our catalyst system for the N-arylation of arylamines with aryl iodides, we investigated the N-arylation of arylamines with aryl bromides. Initially, the model reaction was carried out as previously described, except 4-bromoanisole was used instead of 4-iodoanisole. Interestingly, although the reaction initiated smoothly even at 14 °C, the starting material was difficult to transfer completely to the product at room temperature. Given the necessity of protic solvents for our catalyst system, we envisioned that water could play a role in the reaction. In fact, DEG dried over molecular sieves (4 Å MS) ameliorated the model reaction, affording 79% isolated yield of the desired product in 6 days at room temperature. Molecular sieves are well documented to serve as general catalysts for many reactions. Hence, the model reaction using almost the same conditions, except with anhydrous Na2SO4 instead of 4 Å

In conclusion, we have developed a general and effective method for the CuI-catalyzed amination of aryl iodides and bromides at room temperature. The advantages of this procedure are summarized as follows: (1) a relatively low catalyst/ligand loading (only 5 mol % CuI and ligand) is needed; (2) an organic base is not required to achieve the room-temperature copper-catalyzed amination of aryl halides; (3) only a slight excess of amine (1.3 equiv) is required for complete amination; (iv) chemoselectivity between −OH groups (alcohols and phenol) and −NH2 groups (aliphatic and arylamines) is realized, and the reaction has a universal substrate scope (including aryl bromides and aryl iodides and aliphatic and aryl amines), irrespective of the substrate’s electronic and steric effects; and (4) raising the reaction temperature could largely shorten the reaction time as expected without a change of the reaction selectivity. Together, these benefits make this catalytic system more practical than other procedures.

■

EXPERIMENTAL SECTION

General Information. All starting materials and reagents are analytical grade, commercially available, and used as received, unless otherwise mentioned. Aryl halides and amines were purchased from Alfa Aesar and J&K Co. Diethylene glycol (DEG) was purchased from J&K Co. and dried with molecular sieves (4 Å). All C−N coupling reactions were carried out at room temperature in vials (size: 10 mL) sealed with a septum. Flash column chromatography (flash cc) was

5418

DOI: 10.1021/acs.joc.7b00290 J. Org. Chem. 2017, 82, 5416−5423

Note

The Journal of Organic Chemistry

109.3, 55.7; IR (KBr, cm−1) 3408, 3233, 1607, 1507. Anal. Calcd for C19H19N3O3·0.02H2O: C, 67.57; H, 5.68; N, 12.44. Found: C, 67.31; H, 5.64; N, 12.81. N′,N′-Bis(4-nitrophenyl)-1H-pyrrole-2-carbohydrazide (L5): 312 mg, 85%; yellow solid; mp 238−240 °C; MS(EI+) m/z 367 (M+, 5); 94 (M+-NHN(PhNO2)2,100) 1H NMR (400 MHz, DMSO-d6) δ 11.80 (s, 1H), 11.38 (s, 1H), 8.25 (d, J = 9.2 Hz, 4H), 7.45 (d, J = 9.2 Hz, 4H), 7.05−7.03 (m, 2H), 6.22−6.21 (m, 1H); 13C NMR (100 MHz, DMSO-d6) δ 160.3, 150.5, 142.6, 126.0, 124.1, 123.3, 119.4, 112.5, 109.8; IR (KBr, cm−1) 3309, 1650, 1582. Anal. Calcd for C18H16N5O5·0.3H2O: C, 54.78; H, 3.68; N, 18.79. Found: C, 54.71; H, 3.40; N, 19.01. N′-Phenyl-N′-(o-tolyl)-1H-pyrrole-2-carbohydrazide (L6). A three-neck flask was charged with N′-phenyl-1H-pyrrole- 2-carbohydrazide (201 mg, 1 mmol), 2-iodotoluene (262 mg, 1.2 mmol), CuI (38 mg, 0.02 mmol), and Cs2CO3 (652 mg, 2 mmol) under nitrogen atmosphere. After DMSO (2 mL) was injected, the reaction mixture was stirred at 55 °C until N′-phenyl-1H-pyrrole-2-carbohydrazide disappeared as monitored by TLC. The cooled reaction mixture was poured into water and extracted with ethyl acetate (3 × 20 mL). The combined organic phase was washed with brine, dried over Na2SO4, and concentrated in vacuo. The residue was purified with flash cc on silica gel eluting with petroleum ether/ethyl acetate (10:1 and 3:1 stepwise) to provide L6: 210 mg, 72%; white solid; mp 249−250 °C; MS (ESI+) m/z 314 ([M + Na]+); 1H NMR (400 MHz, DMSO-d6) δ 11.56 (s, 1H), 10.62 (s, 1H), 7.50 (d, J = 7.8 Hz, 1H), 7.29−7.16 (m, 5H), 6.97−6.95 (m, 2H), 6.78 (t, J = 7.2 Hz, 1H), 6.55 (d, J = 8.1 Hz, 2H), 6.16−6.14 (m, 1H), 2.25 (s, 3H); 13C NMR (100 MHz, DMSOd6) δ 160.6, 148.0, 144.2, 135.8, 131.2, 129.4, 127.7, 127.0, 126.9, 124.3, 123.0, 119.3, 113.5, 111.3, 109.4, 18.5; IR (KBr, cm−1) 3404, 3236, 1644, 1594. Anal. Calcd for C19H19N3O·0.03H2O: C, 74.07; H, 5.89; N, 14.40. Found: C, 73.80; H, 5.79; N, 14.74. (E)-(Phenyldiazenyl)(1H-pyrrol-2-yl)methanone (B). A threeneck flask was charged with N′-phenyl-1H-pyrrole-2-carbohydrazide (201 mg, 1 mmol), 2 mL of MeCN, and Cs2CO3 (652 mg, 2 mmol) and stirred at room temprature until N′-phenyl-1H-pyrrole-2carbohydrazide disappeared as monitored by TLC. The reaction mixture was poured into water and extracted with ethyl acetate (3 × 20 mL). The combined organic phase was washed with brine, dried over Na2SO4, and concentrated in vacuo. The residue was purified with flash cc on silica gel (eluting with 10:1 petroleum ether/ethyl acetate) to provide B (119 mg, 60%): red solid; mp 110−111 °C; MS(ESI+) m/z 200 ([M + H]+); 1H NMR (400 MHz, DMSO-d6) δ 12.30 (s, 1H), 7.82 (d, J = 6.8 Hz, 2H), 7.62−7.43 (m, 3H), 7.24 (s, 1H), 6.77 (d, J = 2.3 Hz, 1H), 6.19 (s, 1H); 13C NMR (100 MHz, DMSO-d6) δ 174.4, 153.4, 135.3, 131.5, 130.8, 125.8, 124.9, 122.4, 113.1; IR (KBr, cm−1) 3204, 1671. Anal. Calcd for C11H9N3O: C, 66.32; H, 4.55; N, 21.09. Found: C, 66.41; H, 4.57; N, 21.30. General Procedure A. A 10 mL vial was charged with CuI (9.5 mg, 0.05 mmol), L1 (13.8 mg, 0.05 mmol), aryl iodides (1.0 mmol), amine (1.3 mmol), K3PO4 (424 mg, 2.0 mmol), DEG (2.0 mL), and a magnetic stir bar. The vessel was sealed with a septum. The reaction mixture was stirred at room temperature for 12−15 h and then quenched with 2 mL water. Water (15 mL) was added to the mixture followed by extraction with ethyl acetate (3 × 15 mL). The combined organic phase was washed with brine (15 mL), dried over anhydrous Na2SO4, and concentrated in vacuo. The residue was purified with flash cc on silica gel to afford the target compound. General Procedure B. A 10 mL of vial was charged with CuI (10 mg, 0.05 mmol), L1 (13.8 mg, 0.05 mmol), aryl bromides (1.0 mmol), amine (1.3 mmol), K3PO4 (424 mg, 2.0 mmol), DEG (2.0 mL), molecular sieves (4 Å-MS, 100 mg), and a magnetic stir bar. The vessel was sealed with a septum. The reaction mixture was stirred at room temperature for 6−6.5 d and then quenched with 2 mL water. TWater (15 mL) was added to the mixture followed by extraction with ethyl acetate (3 × 15 mL). The combined organic phase was washed with brine (15 mL), dried over anhydrous Na2SO4, and concentrated in vacuo. The residue was purified with flash cc on silica gel to afford the target compound.

performed on silica gel (200−300 mesh). Thin-layer chromatography was carried out with Merck silica gel GF254 plates. All of the known compounds were characterized by MS, 1H NMR, and 13C NMR, which were compared with the previously reported data. All of the new compounds were also characterized by elemental analytical and IR data in addition. 1H and 13C NMR spectra were recorded at rt on a Bruker AVANCEIII 400 MHz instrument with TMS as an internal reference. ESI-MS was run on a LCMS-2010A. EI mass spectra were recorded on the Thermo DSQ mass spectrometer. GC−MS was run on a Finnigan Voyager with an electron-impact (70 eV) mass selective detector and an innowax 30 m × 0.25 mm × 0.25 μm capillary apolar column. GC− MS method: initial temperature, 50 °C; initial time, 3 min; ramp, 20 °C/min; final temperature, 250 °C; final time, 2 min. Element analyses were carried out with a Vario EL series analyzer within errors of ±0.4% for CHN elements. The IR spectra were recorded on a Thermo Nicolet Avatar 330 FT-IR. Melting points were determined on a WRS1B digital melting point apparatus, and the thermometer was not calibrated. The single crystals were grown from methanol (L3) and the mixture of chloroform and hexane (B). Single-crystal X-ray diffraction data were collected at 293(2) K on an Oxford Germini S Ultra diffractometer or an Agilent SuperNova, Dual, Cu at zero, Atlas S2 diffractometer, with Cu Kα radiation (λ = 1.54178 Å). The CIF files for the crystal structures have been deposited with the CCDC and been given the deposition numbers 1527350 (B) and 1527351 (L3). General Procedure for Synthesis of L1−L5. A three-neck flask was charged with 1H-pyrrole-2-carbohydrazide (125 mg, 1 mmol,) aryl iodides (2.4 mmol), CuI (38 mg, 0.2 mmol), and Cs2CO3 (652 mg, 2 mmol) under nitrogen atmosphere. After DMSO (2 mL) was injected, the reaction mixture was stirred at 55 °C until N-monosubstituted 1Hpyrrole-2-carbohydrazide was completely consumed as indicated by TLC. The cooled reaction mixture was poured into water and extracted with ethyl acetate (3 × 20 mL). The combined organic phase was washed with brine, dried over Na2SO4, and concentrated in vacuo. The residue was purified by flash cc on silica gel eluting with petroleum ether/ethyl acetate (10:1 and 3:1 stepwise) to provide the desired products. N′,N′-Diphenyl-1H-pyrrole-2-carbohydrazide (L1): 216 mg, 78%; white solid; mp 238−239 °C; MS(ESI+) m/z 300 ([M + Na]+); 1H NMR (400 MHz, DMSO-d6) δ 11.63 (s, 1H), 10.76 (s, 1H), 7.31− 7.28 (m, 4H), 7.16−7.14 (m, 4H), 7.00−6.98 (m, 4H); 13C NMR (100 MHz, DMSO-d6) δ 160.7, 146.5, 129.5, 124.3, 123.1, 122.4, 119.1, 111.4, 109.4; IR (KBr, cm−1) 3411, 3239, 1613, 1587. Anal. Calcd for C17H15N3O·0.1H2O: C, 73.15; H, 5.49; N, 15.05. Found: C, 73.27; H, 5.41; N, 15.34. N′,N′-Bis(2-isopropylphenyl)-1H-pyrrole-2-carbohydrazide (L2): 245 mg, 68%; white solid; mp 212−214 °C; MS(ESI+) m/z 362 ([M + H]+); 1H NMR (400 MHz, DMSO-d6) δ 11.40 (s, 1H), 10.45 (s, 1H), 7.30−7.28 (m, 2H), 7.11−7.03 (m, 6H), 6.90−6.86 (m, 2H), 6.08 (d, J = 2.1 Hz, 1H), 3.45−3.40 (m, 2H), 1.03 (d, J = 55.6 Hz, 12H); 13C NMR (100 MHz, DMSO-d6) δ 159.0, 146.8, 143.6, 127.0, 126.2, 125.3, 125.0, 123.2, 122.3, 110.7, 109.2, 26.9, 24.1, 23.2; IR (KBr, cm − 1 ) 3367, 3265, 1657, 1554. Anal. Calcd for C23H17N3O•0.2H2O: C, 75.67; H, 7.56; N, 11.51. Found: C, 75.53; H, 7.48; N, 11.79. N′,N′-Di-o-tolyl-1H-pyrrole-2-carbohydrazide (L3): 223 mg, 73%; white solid; mp 214−215 °C; MS(ESI+) m/z 328 ([M + Na]+); 1H NMR (400 MHz, DMSO-d6) δ 11.42 (s, 1H), 10.50 (s, 1H), 7.17− 7.10 (m, 4H), 7.01−6.97 (m, 4H), 6.93−6.91 (m, 2H), 6.12−6.10 (m, 1H), 2.04 (s, 6H); 13C NMR (100 MHz, DMSO-d6) δ 159.5, 146.8, 131.8, 131.6, 126.7, 124.6, 124.1, 122.6, 122.0, 110.9, 109.3, 18.7; IR (KBr, cm−1) 3403, 3256, 1641, 1598. Anal. Calcd for C19H19N3O· 0.08H2O: C, 74.38; H, 6.29; N, 13.70. Found: C, 74.29; H, 6.21; N, 13.99. N′,N′-Bis(4-methoxyphenyl)-1H-pyrrole-2-carbohydrazide (L4): 253 mg, 75%; white solid; mp 230−231 °C; MS(ESI+) m/z 360 ([M + Na]+); 1H NMR (400 MHz, DMSO-d6) δ 11.53 (s, 1H), 10.54 (s, 1H), 7.01 (d, J = 8.8 Hz, 4H), 6.95−6.93 (m, 2H), 6.86 (d, J = 8.8 Hz, 4H), 6.14−5.13 (m, 1H), 3.70 (s, 6H); 13C NMR (100 MHz, DMSO-d6) δ 160.7, 154.9, 141.0, 124.5, 122.8, 120.6, 114.7, 111.2, 5419

DOI: 10.1021/acs.joc.7b00290 J. Org. Chem. 2017, 82, 5416−5423

Note

The Journal of Organic Chemistry

δ 7.27 (t, J = 7.8 Hz, 2H), 7.20 (d, J = 8.5 Hz, 2H), 7.04 (d, J = 7.9 Hz, 2H), 7.01−6.92 (m, 3H); 13C NMR (100 MHz, CDCl3) δ 142.7, 142.0, 129.5, 129.3, 125.5, 121.6, 118.9, 118.2. 1-(4-(Phenylamino)phenyl)ethanone (6a).19 General procedure A (179 mg, 85%), eluting with dichloromethane/methanol (20:1): yellow solid; 1H NMR (400 MHz, CDCl3) δ 7.86 (d, J = 8.3 Hz, 2H), 7.34 (t, J = 7.6 Hz, 2H), 7.18 (d, J = 7.8 Hz, 2H), 7.08 (t, J = 7.3 Hz, 1H), 6.99 (d, J = 8.2 Hz, 2H), 6.22 (s, 1H), 2.52 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 196.8, 148.7, 140.8, 130.7, 129.5, 123.2, 120.7, 114.4, 26.2. 4-Nitro-N-phenylaniline (7a).19 General procedure C (156 mg, 73%), general procedure D, eluting with petroleum ether/ethyl acetate (10:1), (134 mg, 63%), general procedure F (161 mg, 75%): yellow solid; 1H NMR (400 MHz, CDCl3) δ 8.14 (d, J = 9.1 Hz, 2H), 7.42 (t, J = 7.9 Hz, 2H), 7.29−7.20 (m, 3H), 6.97 (d, J = 9.1 Hz, 2H); 13C NMR (100 MHz, CDCl3) δ 150.4, 139.5, 129.7, 126.3, 124.6, 121.9, 113.7, 29.7. N-Phenyl-4-(trifluoromethyl)aniline (8a).19 General procedure A (190 mg, 80%), general procedure B (170 mg, 72%), general procedure E (194 mg, 82%), general procedure F (201 mg, 85%), eluting with petroleum ether/ethyl acetate (20:1): white solid; 1H NMR (400 MHz, CDCl3) δ 7.47 (d, J = 8.3 Hz, 2H), 7.33 (t, J = 7.6 Hz, 2H), 7.15 (d, J = 8.0 Hz, 2H), 7.09−7.01 (m, 3H); 13C NMR (100 MHz, CDCl3) δ 146.8, 141.2, 129.6, 126.8, 126.7, 126.7, 123.0, 121.8, 121.5, 120.1, 115.4. 2-Methoxy-N-phenylaniline (9a).15a General procedure A (141 mg, 71), general procedure B (140 mg,71%), general procedure E (171 mg, 86%), general procedure F (165 mg, 83%), eluting with petroleum ether/ethyl acetate (20:1): colorless oil; 1H NMR (400 MHz, CDCl3) δ 7.32−7.23 (m, 3H), 7.15 (d, J = 8.1 Hz, 2H), 6.95− 6.86 (m, 4H), 3.87 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 148.4, 142.7, 133.0, 129.3, 121.2, 120.9, 120.0, 118.6, 114.8, 110.6, 55.6. 3,5-Dimethyl-N-phenylaniline (10a).21 General procedure A (183 mg, 93%), eluting with petroleum ether/ethyl acetate (20:1): white solid; 1H NMR (400 MHz, CDCl3) δ 7.25 (t, J = 7.7 Hz, 2H), 7.05 (d, J = 8.0 Hz, 2H), 6.91 (t, J = 7.3 Hz, 1H), 6.70 (s, 2H), 6.59 (s, 1H), 2.26 (s, 6H); 13C NMR (100 MHz, CDCl3) δ 143.5, 143.2, 139.1, 129.4, 123.0, 120.9, 118.0, 115.8, 21.5. N-Phenylbenzo[d][1,3]dioxol-5-amine (11a).15a General procedure A (170 mg, 80%), general procedure F (177 mg, 83%), eluting with petroleum ether/ethyl acetate (10:1): colorless oil; 1H NMR (400 MHz, CDCl3) δ 7.24 (t, J = 7.5 Hz, 2H), 6.94 (d, J = 7.9 Hz, 2H), 6.88 (t, J = 7.3 Hz, 1H), 6.75 (d, J = 8.2 Hz, 1H), 6.71 (s, 1H), 6.56 (d, J = 8.2 Hz, 1H), 5.93 (s, 2H); 13C NMR (100 MHz, CDCl3) δ 148.3, 144.7, 142.9, 137.3, 129.4, 120.1, 116.4, 113.0, 108.6, 102.6, 100.1. N-Phenylthiophen-3-amine (12a).21 General procedure A (151 mg, 86%), general procedure B (122 mg, 70%), general procedure E (151 mg, 86%), general procedure F (145 mg, 83%), eluting with petroleum ether/ethyl acetate (20:1): colorless oil; 1H NMR (400 MHz, CDCl3) δ 7.26−7.22 (m, 3H), 7.00 (d, J = 7.8 Hz, 2H), 6.95 (d, J = 5.0 Hz, 1H), 6.90 (t, J = 7.3 Hz, 1H), 6.78 (s, 1H); 13C NMR (100 MHz, CDCl3) δ 144.7, 141.6, 129.5, 129.4, 125.2, 122.9, 119.9, 115.6, 106.5. N-Phenylpyridin-2-amine (13a).15a General procedure B (119 mg, 70%), general procedure F (138 mg, 81%), eluting with dichloromethane/methanol (20:1): white solid; 1H NMR (400 MHz, CDCl3) δ 8.20 (d, J = 4.6 Hz, 1H), 7.47 (t, J = 7.8 Hz, 1H), 7.33−7.25 (m, 4H), 7.06−7.03 (m, 2H), 6.88 (d, J = 8.4 Hz, 1H), 6.73−6.70 (m, 1H); 13C NMR (100 MHz, CDCl3) δ 156.1, 148.3, 140.5, 137.7, 129.3, 122.8, 120.4, 115.0, 108.2. 2-(Allyloxy)-N-phenylaniline (14a). General procedure A (187 mg, 83%), eluting with petroleum ether: colorless oil, ;MS(ESI+) m/z 226 ([M + H]+); 1H NMR (400 MHz, CDCl3) δ 7.34−7.24 (m, 3H), 7.15 (d, J = 7.8 Hz, 2H), 6.97−6.78 (m, 4H), 6.14−6.01 (m, 1H), 5.40 (d, J = 17.2 Hz, 1H), 5.29 (d, J = 10.5 Hz, 1H), 4.59 (d, J = 5.2 Hz, 2H). 13 C NMR (100 MHz, CDCl3) δ 147.3, 142.8, 133.4, 129.4, 121.3, 121.2, 119.9, 118.8, 117.9, 114.9, 112.2, 69.6; IR (KBr, cm−1) 3415, 1230, 1648. Anal. Calcd for C15H15NO·0.3H2O: C, 78.10; H, 6.82; N, 6.07. Found: C, 78.21; H, 6.80; N, 5.89.

General Procedure C. A 10 mL vial was charged with CuI (9.5 mg, 0.05 mmol), L2 (18 mg, 0.05 mmol), aryl iodides (1.0 mmol), amine (1.3 mmol), K3PO4 (424 mg, 2.0 mmol), DEG (2.0 mL), and a magnetic stir bar. The vessel was sealed with a septum. The reaction mixture was stirred at room temperature for 15 h and then quenched with 2 mL water. Water (15 mL) was added to the mixture followed by extraction with ethyl acetate (3 × 15 mL). The combined organic phase was washed with brine (15 mL), dried over anhydrous Na2SO4, and concentrated in vacuo. The residue was purified with flash cc on silica gel to afford the target compound. General Procedure D. A 10 mL vial was charged with CuI (9.5 mg, 0.05 mmol), L2 (18 mg, 0.05 mmol), aryl bromides (1.0 mmol), amine (1.3 mmol), K3PO4 (424 mg, 2.0 mmol), DEG (2.0 mL), molecular sieves (4 Å MS, 100 mg), and a magnetic stir bar. The vessel was sealed with a septum. The reaction mixture was stirred at room temperature for 6.5 d and then quenched with 2 mL water. Water (15 mL) was added to the mixture followed by extraction with ethyl acetate (3 × 15 mL). The combined organic phase was washed with brine (15 mL), dried over anhydrous Na2SO4, and concentrated in vacuo. The residue was purified with flash cc on silica gel to afford the target compound. General Procedure E. A 10 mL vial was charged with CuI (9.5 mg, 0.05 mmol), L1 (13.8 mg, 0.05 mmol), aryl iodides (1.0 mmol), amine (1.3 mmol), K3PO4 (424 mg, 2.0 mmol), DEG (2.0 mL), and a magnetic stir bar. The vessel was sealed with a septum. The reaction mixture was stirred at 50 °C for 1 h and then quenched with 2 mL water. Water (15 mL) was added to the mixture followed by extraction with ethyl acetate (3 × 15 mL). The combined organic phase was washed with brine (15 mL), dried over anhydrous Na2SO4, and concentrated in vacuo. The residue was purified with flash cc on silica gel to afford the target compound. General Procedure F. A 10 mL of vial was charged with CuI (10 mg, 0.05 mmol), L1 (13.8 mg, 0.05 mmol), aryl bromides (1.0 mmol), amine (1.3 mmol), K3PO4 (424 mg, 2.0 mmol), DEG (2.0 mL), molecular sieves (4 Å-MS, 100 mg), and a magnetic stir bar. The vessel was sealed with a septum. The reaction mixture was stirred at 60 °C for 3 h and then quenched with 2 mL water. Water (15 mL) was added to the mixture followed by extraction with ethyl acetate (3 × 15 mL). The combined organic phase was washed with brine (15 mL), dried over anhydrous Na2SO4, and concentrated in vacuo. The residue was purified with flash cc on silica gel to afford the target compound. 4-Methoxy-N-phenylaniline (1a).19 General procedure A (180 mg, 90%), general procedure B (158 mg, 79%), general procedure E (181 mg, 91%), general procedure F (181 mg, 91%), eluting with petroleum ether/ethyl acetate (20:1): white solid; 1H NMR (400 MHz, CDCl3) δ 7.27−7.17 (m, 2H), 7.13−7.02 (m, 2H), 6.97−6.80 (m, 5H), 3.79 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 155.3, 145.2, 135.8, 129.4, 122.2, 119.6, 115.7, 114.7, 55.6. 4-(Phenylamino)phenol (2a).20 General procedure A (155 mg, 84%), eluting with petroleum ether/ethyl acetate (10:1): white solid; 1 H NMR (400 MHz, CDCl3) δ 7.22 (t, J = 7.8 Hz, 2H), 7.03 (d, J = 8.3 Hz, 2H), 6.91 (d, J = 7.8 Hz, 2H), 6.84 (t, J = 7.3 Hz, 1H), 6.79 (d, J = 8.7 Hz, 2H); 13C NMR (100 MHz, CDCl3) δ 151.1, 145.2, 135.8, 129.4, 122.5, 119.7, 116.2, 115.8. 4-Methyl-N-phenylaniline (3a).19 General procedure A (159 mg, 87%), general procedure B (148 mg, 81%), general procedure E (157 mg, 86%), general procedure F (161 mg, 88%), eluting with petroleum ether/ethyl acetate (20:1): white solid; 1H NMR (400 MHz, CDCl3) δ 7.23 (t, J = 7.6 Hz, 2H), 7.11−7.06 (m, 2H), 7.04−6.97 (m, 4H), 6.88 (t, J = 7.2 Hz, 1H), 2.30 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 144.0, 140.3, 131.0, 129.9, 129.4, 120.4, 119.0, 116.9, 20.8. Diphenylamine (4a).19 General procedure A (152 mg, 90%), general procedure B (133 mg, 79%), general procedure E (147 mg, 87%), general procedure F (152 mg, 90%), eluting with petroleum ether/ethyl acetate (20:1): white solid; 1H NMR (400 MHz, CDCl3) δ 7.26 (t, J = 7.6 Hz, 4H), 7.07 (d, J = 8.0 Hz, 4H), 6.92 (t, J = 7.3 Hz, 2H); 13C NMR (100 MHz, CDCl3) δ 143.3, 129.5, 121.2, 118.0. 4-Chloro-N-phenylaniline (5a).19 General procedure A (158 mg, 78%), general procedure F (164 mg, 81%), eluting with petroleum ether/ethyl acetate (20:1): white solid; 1H NMR (400 MHz, CDCl3) 5420

DOI: 10.1021/acs.joc.7b00290 J. Org. Chem. 2017, 82, 5416−5423

Note

The Journal of Organic Chemistry

solid; 1H NMR (400 MHz, CDCl3) δ 6.97 (d, J = 8.0 Hz, 2H), 6.74 (d, J = 8.0 Hz, 2H), 2.25 (s, 3H), 2.08 (s, 3H), 1.81 (s, 6H), 1.70−1.58 (m, 6H,); 13C NMR (100 MHz, CDCl3) δ 143.1, 129.4, 129.2, 120.9, 52.4, 43.6, 36.5, 29.8, 20.6. N-Phenyladamantan-1-amine (4h).20 General procedure A (198 mg, 87%), eluting with petroleum ether/ethyl acetate (20:1): white solid; 1H NMR (400 MHz, CDCl3) δ 7.13 (t, J = 7.8 Hz, 2H), 6.78 (d, J = 7.6 Hz, 3H), 3.25 (s, 1H), 2.09 (s, 3H), 1.86 (s, 6H), 1.71−1.61 (m, 6H); 13C NMR (100 MHz, CDCl3) δ 146.1, 128.8, 119.2, 119.1, 52.2, 43.5, 36.5, 29.8. N-Cyclohexyl-4-methoxyaniline (1i).15a General procedure A: 174 mg, 85%, general procedure B (152 mg, 74%), general procedure F (178 mg, 87%), eluting with petroleum ether/ethyl acetate (20:1): white solid; 1H NMR (400 MHz, CDCl3) δ 6.76 (d, J = 8.4 Hz, 2H), 6.58 (d, J = 8.3 Hz, 2H), 3.74 (s, 3H), 3.21−3.09 (m, 1H), 2.08−1.98 (m, 2H), 1.78−1.68 (m, 2H), 1.68−1.59 (m, 1H), 1.42−1.28 (m, 2H), 1.26−1.06 (m, 3H); 13C NMR (100 MHz, CDCl3) δ 152.0, 141.5, 115.0, 55.8, 52.9, 33.6, 26.0, 25.1. 1-(4-Methoxyphenyl)piperidine (1j).27 General procedure A (168 mg, 88%), general procedure B (143 mg, 75%), general procedure F (169 mg, 88%), eluting with petroleum ether/ethyl acetate (20:1): colorless oil; 1H NMR (400 MHz, CDCl3) δ 6.93 (d, J = 8.7 Hz, 2H), 6.83 (d, J = 8.8 Hz, 2H), 3.76 (s, 3H), 3.06−2.97 (m, 4H), 1.77−1.68 (m, 4H), 1.60−1.48 (m, 2H); 13C NMR (100 MHz, CDCl3) δ 153.6, 146.9, 118.8, 114.3, 55.6, 52.3, 26.2, 24.2. 1-(p-Tolyl)piperidine (3j).28 General procedure B (135 mg, 77%), eluting with petroleum ether/ethyl acetate (20:1): colorless oil; 1H NMR (400 MHz, CDCl3) δ 7.05 (d, J = 8.2 Hz, 2H), 6.85 (d, J = 8.3 Hz, 2H), 3.11−3.03 (m, 4H), 2.25 (s, 3H), 1.75−1.65 (m, 4H), 1.58− 1.49 (m, 2H); 13C NMR (100 MHz, CDCl3) δ 150.3, 129.6, 128.8, 117.0, 51.4, 26.0, 24.4, 20.5. 1-(4-(Trifluoromethyl)phenyl)piperidine (8j).29 General procedure B (146 mg, 64%), eluting with petroleum ether/ethyl acetate (20:1): colorless oil; 1H NMR (400 MHz, CDCl3) δ 7.44 (d, J = 8.5 Hz, 2H), 6.90 (d, J = 8.5 Hz, 2H), 3.26−3.24 (m, 4H), 1.68−1.61 (m, 3H); 13C NMR (100 MHz, CDCl3) δ 153.8, 128.9, 126.4, 126.3, 126.3, 126.3, 123.6, 120.9, 119.7, 119.4, 114.6, 49.3, 25.4, 24.3. 4-(4-Methoxyphenyl)morpholine (1k).15a General procedure A (170 mg, 88%), general procedure B (131 mg, 68%), general procedure F (170 mg, 88%), eluting with petroleum ether/ethyl acetate (20:1): white solid; 1H NMR (400 MHz, CDCl3) δ 6.92−6.85 (m, 4H), 3.90−3.83 (m, 4H), 3.78 (s, 3H), 3.10−3.03 (m, 4H); 13C NMR (100 MHz, CDCl3) δ 154.1, 145.8, 117.9, 114.5, 67.0, 55.6, 50.9. 4-Phenylmorpholine (3k).15a General procedure A (132 mg, 81%), eluting with petroleum ether/ethyl acetate (20:1): white solid; 1H NMR (400 MHz, CDCl3) δ 7.32−7.24 (m, 2H), 6.97−6.84 (m, 3H), 3.89−3.83 (m, 4H), 3.19−3.13 (m, 4H); 13C NMR (100 MHz, CDCl3) δ 151.2, 129.2, 120.1, 115.8, 66.9, 49.4. 1-(4-Morpholinophenyl)ethanone (6k).15a General procedure A (158 mg, 77%), eluting with dichloromethane/methanol (20:1): yellow solid; 1H NMR (400 MHz, CDCl3) δ 7.90 (d, J = 8.9 Hz, 2H), 6.90 (d, J = 8.9 Hz, 2H), 3.90−3.83 (m, 4H), 3.35−3.28 (m, 4H), 2.53 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 196.5, 154.0, 130.4, 128.4, 113.5, 66.5, 47.7, 26.2. 1-(4-Methoxyphenyl)-4-methylpiperazine (1l).30 General procedure A (172 mg, 83%), general procedure E (179 mg, 87%), general procedure F (177 mg, 86%), eluting with petroleum ether/ethyl acetate (20:1): white solid; 1H NMR (400 MHz, CDCl3) δ 6.93−6.87 (m, 2H), 6.86−6.80 (m, 2H), 3.76 (s, 3H), 3.14−3.06 (m, 4H), 2.61− 2.54 (m, 4H), 2.35 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 153.8, 145.7, 118.2, 114.4, 55.6, 55.3, 50.6, 46.1. 1-(4-Methoxyphenyl)pyrrolidine (1m).21 General procedure A (158 mg, 89%), general procedure F (156 mg, 87%), eluting with petroleum ether/ethyl acetate (20:1): white solid; 1H NMR (400 MHz, CDCl3) δ 6.84 (d, J = 8.5 Hz, 2H), 6.54 (d, J = 8.2 Hz, 2H), 3.75 (s, 3H), 3.30−3.10 (m, 4H), 2.05−1.91 (m, 4H); 13C NMR (100 MHz, CDCl3) δ 150.9, 143.2, 115.1, 112.7, 56.0, 48.4, 25.4. N-Butyl-4-methoxyaniline (1n).15a General procedure A (156 mg, 87%), general procedure B (127 mg, 71%), general procedure E (166 mg, 93%), general procedure F (161 mg, 90%), eluting with petroleum

Bis(4-methoxyphenyl)amine (1b).19 General procedure A (206 mg, 90%), eluting with petroleum ether/ethyl acetate (20:1): white solid; 1H NMR (400 MHz, CDCl3) δ 7.05−6.86 (m, 4H), 6.85−6.78 (m, 4H), 3.78 (s, 6H); 13C NMR (100 MHz, CDCl3) δ 154.2, 138.0, 119.5, 114.7, 55.7. 4-Methoxy-N-(4-nitrophenyl)aniline (7b).22 General procedure C (214 mg, 88%), eluting with petroleum ether/ethyl acetate (10:1): yellow solid; 1H NMR (400 MHz, CDCl3) δ 8.11 (d, J = 9.0 Hz, 2H), 7.18 (d, J = 8.7 Hz, 2H), 6.96 (d, J = 8.7 Hz, 2H), 6.79 (d, J = 9.1 Hz, 2H), 3.86 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 157.4, 151.8, 139.0, 132.0, 126.4, 125.4, 114.9, 112.6, 55.6. 4-((4-Methoxyphenyl)amino)phenol (1c).23 General procedure A (180 mg, 84%), eluting with petroleum ether/ethyl acetate (10:1): white solid; 1H NMR (400 MHz, CDCl3) δ 7.00−6.78 (m, 6H), 6.77− 6.70 (m, 2H), 3.78 (s, 3H); 13C NMR (100 MHz, DMSO-d6 and CDCl3) δ 153.9, 151.5, 138.5, 136.7, 120.5, 118.8, 116.2, 114.7, 55.7. 4-Isopropoxy-N-(4-methoxyphenyl)aniline (1d). General procedure A (210 mg, 82%), eluting with petroleum ether/ethyl acetate (20:1): colorless oil; MS(ESI+) m/z 258 ([M + H]+); 1H NMR (400 MHz, CDCl3) δ 7.04−6.88 (m, 4H), 6.85−6.78 (m, 4H), 4.47−4.41 (m, 1H), 3.78 (s, 3H), 1.31 (d, J = 6.1 Hz, 6H); 13C NMR (126 MHz, CDCl3) δ 154.3, 152.4, 138.0, 119.7, 119.4, 117.4, 114.7, 70.8, 55.7, 22.2; IR (KBr, cm−1) 3386, 1232. Anal. Calcd for C16H19NO2:C, 74.68; H, 7.44; N, 5.44. Found: C, 74.55; H, 7.53; N, 5.67. 2,6-Diisopropyl-N-(4-methoxyphenyl)aniline (1e).24 General procedure A (238 mg, 84%), general procedure F (241 mg, 85%), eluting with petroleum ether/ethyl acetate (20:1): white solid; 1H NMR (400 MHz, CDCl3) δ 7.29−7.16 (m, 3H), 6.73 (d, J = 8.6 Hz, 2H), 6.49− 6.40 (m, 2H), 3.73 (s, 3H), 3.24−3.12 (m, 2H), 1.13 (d, J = 6.9 Hz, 12H); 13C NMR (126 MHz, CDCl3) δ 152.3, 147.1, 142.3, 136.1, 126.8, 123.9, 114.8, 114.3, 55.7, 28.2, 23.9. N-Benzyl-4-methoxyaniline (1g).19 General procedure A (190 mg, 89%), general procedure B (164 mg, 77%), general procedure E (192 mg, 90%), general procedure F (179 mg, 84%), eluting with petroleum ether/ethyl acetate (20:1): white solid; 1H NMR (400 MHz, CDCl3) δ 7.38−7.24 (m, 5H), 6.77 (d, J = 8.9 Hz, 2H), 6.61 (d, J = 8.8 Hz, 2H), 4.28 (s, 2H), 3.73 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 152.3, 142.6, 139.8, 128.7, 127.6, 127.2, 115.0, 114.2, 55.8, 49.3. N-Benzyl-4-methylaniline (3g).19 General procedure A (170 mg, 86%), eluting with petroleum ether/ethyl acetate (20:1): colorless oil; 1 H NMR (400 MHz, CDCl3) δ 7.39−7.20 (m, 5H), 6.97 (d, J = 6.3 Hz, 2H), 6.54 (d, J = 7.6 Hz, 2H), 4.28 (s, 2H), 2.22 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 145.9, 139.7, 129.8, 128.6, 127.6, 127.2, 126.8, 113.1, 48.7, 20.4. N-Benzylaniline (4g).19 General procedure A (164 mg, 89%), eluting with petroleum ether/ethyl acetate (20:1), white solid; 1H NMR (400 MHz, CDCl3) δ 7.37−7.21 (m, 5H), 7.15 (t, J = 7.5 Hz, 2H), 6.70 (t, J = 7.1 Hz, 1H), 6.61 (d, J = 7.8 Hz, 2H), 4.29 (s, 2H); 13 C NMR (100 MHz, CDCl3) δ 148.2, 139.5, 129.3, 128.7, 127.6, 127.3, 117.7, 113.0, 48.4. N-Benzyl-4-nitroaniline (7g).19 General procedure C (164 mg, 72%), general procedure D (137 mg, 60%), eluting with petroleum ether/ethyl acetate (10:1): white solid; 1H NMR (400 MHz, CDCl3) δ 8.06 (d, J = 8.5 Hz, 2H), 7.44−7.25 (m, 5H), 6.56 (d, J = 8.5 Hz, 2H), 4.97 (s, 1H), 4.43 (s, 2H); 13C NMR (100 MHz, CDCl3) δ 153.1, 138.4, 137.4, 128.9, 127.9, 127.3, 126.4, 111.4, 47.7. N-Benzylthiophen-3-amine (12g).25 General procedure A (134 mg, 71%), general procedure F (151 mg, 80%), eluting with petroleum ether/ethyl acetate (20:1): colorless oil; 1H NMR (400 MHz, CDCl3) δ 7.42−7.24 (m, 5H), 7.16−7.12 (m, 1H), 6.63 (d, J = 5.0 Hz, 1H), 5.96 (s, 1H), 4.25 (s, 2H), 3.95 (s, 1H); 13C NMR (100 MHz, CDCl3) δ 148.5, 139.3, 128.6, 127.7, 127.3, 125.2, 119.9, 96.1, 50.7. N-(4-Methoxyphenyl)adamantan-1-amine (1h).20 General procedure A (211 mg, 82%), general procedure F (216 mg, 84%), eluting with petroleum ether/ethyl acetate (20:1): white solid; 1H NMR (400 MHz, CDCl3) δ 6.89−6.82 (m, 2H), 6.78−6.73 (m, 2H), 3.77 (s, 3H), 2.08 (s, 3H), 1.76 (s, 6H), 1.69−1.56 (m, 6H); 13C NMR (100 MHz, CDCl3) δ 154.9, 138.2, 124.3, 113.9, 55.5, 52.7, 43.7, 36.5, 29.7. N-(p-Tolyl)adamantan-1-amine (3h).26 General procedure A (207 mg, 86%), eluting with petroleum ether/ethyl acetate (20:1): white 5421

DOI: 10.1021/acs.joc.7b00290 J. Org. Chem. 2017, 82, 5416−5423

Note

The Journal of Organic Chemistry

NMR (100 MHz, CDCl3) δ 151.1, 143.3, 114.8, 114.5, 55.8, 51.8, 29.5, 20.5, 14.1. N,N-Dibutyl-4-methylaniline (3s).31 General procedure B (112 mg, 51%), eluting with petroleum ether: colorless oil; 1H NMR (400 MHz, CDCl3) δ 7.01 (d, J = 8.0 Hz, 2H), 6.57 (d, J = 8.1 Hz, 2H), 3.24−3.20 (m, 4H), 2.27 (s, 3H), 1.57−1.50 (m, 4H), 1.36−1.26 (m, 4H), 0.93 (t, J = 7.3 Hz, 6H); 13C NMR (100 MHz, CDCl3) δ 146.2, 129.7, 124.4, 112.2, 51.1, 29.5, 20.5, 20.2, 14.1. N,N-Dibutylaniline (4s).36 General procedure A (162 mg, 79%), eluting with petroleum ether: colorless oil; 1H NMR (400 MHz, CDCl3) δ 7.22−7.14 (m, 2H), 6.68−6.55 (m, 3H), 3.25 (t, J = 7.5 Hz, 4H), 1.61−1.50 (m, 4H), 1.42−1.29 (m, 4H), 0.95 (t, J = 7.2 Hz, 6H); 13 C NMR (100 MHz, CDCl3) δ 148.3, 129.2, 115.2, 111.8, 50.8, 29.5, 20.4 14.03. N,N-Dibutyl-4-(trifluoromethyl)aniline (8s).35 General procedure A (218 mg, 80%), general procedure B (82 mg, 30%), eluting with petroleum ether: colorless oil; 1H NMR (400 MHz, CDCl3) δ 7.40 (d, J = 8.5 Hz, 2H), 6.62 (d, J = 8.3 Hz, 2H), 3.32−3.25 (m, 4H), 1.62− 1.51 (m, 4H), 1.41−1.30 (m, 4H), 0.96 (t, J = 7.3 Hz, 6H); 13C NMR (100 MHz, CDCl3) δ 150.2, 138.0, 126.6, 126.4, 123.9, 110.6, 50.7, 29.2, 20.3, 13.9. N,N-Dibutyl-4-(thiophene-3-yl)aniline (12s): 35 General procedure A (148 mg, 70%), general procedure F (167 mg, 79%), eluting with petroleum ether: colorless oil; 1H NMR (400 MHz, CDCl3) δ 7.17 (d, J = 2.6 Hz, 1H), 6.73 (d, J = 5.0 Hz, 1H), 5.80 (s, 1H), 3.18−3.11 (m, 4H), 1.58−1.49 (m, 4H), 1.38−1.27 (m, 4H), 0.93 (t, J = 7.3 Hz, 6H); 13 C NMR (100 MHz, CDCl3) δ 150.5, 124.6, 118.9, 94.6, 52.3, 29.5, 20.4, 14.0. Synthesis of 2-((2-Bromophenyl)thio)aniline (15t).15a A 10 mL vial was charged with CuI (9.5 mg, 0.05 mmol), L1 (13.7 mg, 0.05 mmol), 1-bromo-2-iodobenzene (283 mg, 1.0 mmol), 2-aminobenzenethiol (163 mg, 1.3 mmol), K3PO4 (424 mg, 2.0 mmol), DEG (2.0 mL), and a magnetic stir bar. The vessel was sealed with a septum. The reaction mixture was stirred at room temperature for 12 h. Then 15 mL water was added, and the reaction mixture was extracted with ethyl acetate (3 × 15 mL). The combined organic phases were washed with brine (15 mL), dried over anhydrous Na2SO4, and concentrated in vacuo. The residue was purified using flash column chromatography on silica gel eluting with petroleum ether/ethyl acetate (20:1) to afford 2-((2-bromophenyl)thio)aniline (233 mg, 84%): yellow solid; 1H NMR (400 MHz, CDCl3) δ 7.48 (d, J = 7.9 Hz, 1H), 7.42 (d, J = 7.6 Hz, 1H), 7.25 (t, J = 7.7 Hz, 1H), 7.06 (t, J = 7.6 Hz, 1H), 6.93 (t, J = 7.5 Hz, 1H), 6.77 (dd, J = 16.2, 8.0 Hz, 2H), 6.59 (d, J = 7.9 Hz, 1H), 4.19 (s, 2H); 13C NMR (100 MHz, CDCl3) δ 149.1, 138.0, 137.9, 132.8, 131.8, 127.8, 126.3, 126.3, 120.7, 119.1, 115.6, 113.2. Synthesis of 10H-Phenothiazine (15u).15a A 10 mL vial was charged with CuI (9.5 mg, 0.05 mmol), L1 (13.8 mg, 0.05 mmol), 2((2-bromophenyl)thio)aniline (280 mg, 1.0 mmol), K3PO4 (424 mg, 2.0 mmol), DEG (2.0 mL), molecular sieves (4 Å MS, 100 mg), and a magnetic stir bar. The vessel was sealed with a septum. The reaction mixture was stirred at room temperature for 5 d. Then 15 mL water was added, and the reaction mixture was extracted with ethyl acetate (3 × 15 mL). The combined organic phases were washed with brine (15 mL), dried over anhydrous Na2SO4, and concentrated in vacuo. The residue was purified using flash column chromatography on silica gel eluting with petroleum ether/ethyl acetate (20:1) to afford 10Hphenothiazine (133 mg, 67%): green solid; 1H NMR (400 MHz, DMSO-d6) δ 6.99 (t, J = 7.6 Hz, 2H), 6.91 (d, J = 7.5 Hz, 2H), 6.78− 6.68 (m, 4H); 13C NMR (100 MHz, DMSO-d6) δ 142.6, 128.0, 126.7, 122.2, 116.8, 114.9. One-Pot Synthesis of 10H-Phenothiazine (15u). A 10 mL vial was charged with CuI (10 mg, 0.05 mmol), L1 (13.7 mg, 0.05 mmol), 1-bromo-2-iodobenzene (283 mg, 1.0 mmol), 2-aminobenzenethiol (163 mg, 1.3 mmol), K3PO4 (1060 mg, 5.0 mmol), DEG (2.0 mL), and a magnetic stir bar. The vessel was sealed with a septum. The reaction mixture was stirred at 90 °C for 7 h. Then, 15 mL water was added, and the reaction mixture was extracted with ethyl acetate (3 × 15 mL). The combined organic phases were washed with brine (15 mL), dried over anhydrous Na2SO4, and concentrated in vacuo. The

ether/ethyl acetate (20:1): colorless oil; 1H NMR (400 MHz, CDCl3) δ 6.78 (d, J = 8.9 Hz, 2H), 6.58 (d, J = 8.9 Hz, 2H), 3.74 (s, 3H), 3.06 (t, J = 7.1 Hz, 2H), 1.64−1.54 (m, 2H), 1.46−1.37 (m, 2H), 0.95 (t, J = 7.3 Hz, 3H); 13C NMR (100 MHz, CDCl3) δ 152.0, 142.9, 114.9, 114.0, 55.8, 44.7, 31.8, 20.4, 14.0. N-Butyl-4-methylaniline (3n).31 General procedure B (135 mg, 83%), eluting with petroleum ether/ethyl acetate (20:1); colorless oil; 1 H NMR (400 MHz, CDCl3) δ 6.98 (d, J = 8.1 Hz, 2H), 6.55 (d, J = 8.2 Hz, 2H), 3.08 (t, J = 7.1 Hz, 2H), 2.23 (s, 3H), 1.65−1.51 (m, 2H), 1.46−1.35 (m, 2H), 0.95 (t, J = 7.3 Hz, 3H); 13C NMR (100 MHz, CDCl3) δ 146.3, 129.7, 126.4, 113.0, 44.1, 31.7, 20.4, 20.4, 14.0. N-Butyl-4-nitroaniline (7n).19 General procedure C (132 mg, 68%), general procedure D (116 mg, 60%), eluting with petroleum ether/ethyl acetate (20:1): yellow solid; 1H NMR (400 MHz, CDCl3) δ 8.07 (d, J = 9.1 Hz, 2H), 6.52 (d, J = 9.1 Hz, 2H), 4.67 (s, 1H), 3.21 (t, J = 7.1 Hz, 2H), 1.69−1.59 (m, 2H), 1.50−1.38 (m, 2H), 0.97 (t, J = 7.3 Hz, 3H); 13C NMR (100 MHz, CDCl3) δ 153.6, 137.5, 126.5, 110.9, 43.1, 31.1, 20.2, 13.8. 2-((4-Methoxyphenyl)amino)ethanol (1o).32 General procedure A (142 mg, 85%), general procedure E (144 mg, 86%), general procedure F (144 mg, 86%), eluting with dichloromethane/methanol (20:1): colorless oil; 1H NMR (400 MHz, CDCl3) δ 6.79 (d, J = 8.9 Hz, 2H), 6.65 (d, J = 8.8 Hz, 2H), 3.84−3.78 (m, 2H), 3.75 (s, 3H), 3.28−3.19 (m, 2H); 13C NMR (100 MHz, CDCl3) δ 152.5, 142.2, 115.0, 114.9, 60.9, 55.8, 47.2. 3-((4-Methoxyphenyl)amino)propan-1-ol (1p).33 General procedure A (134 mg, 74%), eluting with dichloromethane/methanol (20:1): colorless oil; general procedure B (103 mg, 57%); 1H NMR (400 MHz, CDCl3) δ 6.79 (d, J = 8.9 Hz, 2H), 6.64 (d, J = 8.9 Hz, 2H), 3.80 (t, J = 5.8 Hz, 2H), 3.75 (s, 3H), 3.24 (t, J = 6.4 Hz, 2H), 1.90−1.81 (m, 2H); 13C NMR (100 MHz, CDCl3) δ 152.3, 142.5, 114.9, 114.8, 61.3, 55.8, 43.0, 31.8. 3-(Phenylamino)propan-1-ol (3p).34 General procedure A (98 mg, 65%), general procedure B (83 mg, 55%), eluting with dichloromethane/methanol (20:1): colorless oil; 1H NMR (400 MHz, CDCl3) δ 7.18 (t, J = 7.6 Hz, 2H), 6.72 (t, J = 7.2 Hz, 1H), 6.64 (d, J = 8.1 Hz, 2H), 3.78 (t, J = 5.8 Hz, 2H), 3.26 (t, J = 6.4 Hz, 2H), 1.90−1.78 (m, 2H); 13C NMR (100 MHz, CDCl3) δ 148.2, 129.3, 117.8, 113.2, 61.6, 42.0, 31.9. 3-((4-(Trifluoromethyl)phenyl)amino)propan-1-ol (8p). General procedure A (175 mg, 80%), eluting with dichloromethane/methanol (20:1): colorless oil; MS(ESI+) m/z 220 ([M + H]+); 1H NMR (400 MHz, CDCl3) δ 7.39 (d, J = 8.4 Hz, 2H), 6.62 (d, J = 8.4 Hz, 2H), 3.81 (t, J = 5.8 Hz, 2H), 3.30 (t, J = 6.1 Hz, 2H), 1.93−1.83 (m, 2H); 13 C NMR (100 MHz, CDCl3) δ 150.7, 126.6, 126.5, 126.3, 123.7, 119.0 118.6, 112.0, 61.3, 41.3, 31.5; IR (KBr, cm−1) 3409, 2944. Anal. Calcd for C10H12F3NO: C, 54.79; H, 5.52; N, 6.39. Found: C, 54.52; H,5.54; N, 6.02. 5-((4-Methoxyphenyl)amino)pentan-1-ol (1q). General procedure A (173 mg, 83%), eluting with dichloromethane/methanol (20:1: colorless oil; MS(ESI+) m/z 210 ([M + H]+); 1H NMR (400 MHz, CDCl3) δ 6.78 (d, J = 8.8 Hz, 2H), 6.59 (d, J = 8.8 Hz, 2H), 3.75 (s, 3H), 3.65 (t, J = 6.4 Hz, 2H), 3.08 (t, J = 7.0 Hz, 2H), 1.68−1.57 (m, 4H), 1.53−1.43 (m, 2H); 13C NMR (100 MHz, CDCl3) δ 152.1, 142.7, 114.9, 114.4, 62.4, 55.8, 45.1, 32.4, 29.3, 23.4. IR (KBr, cm−1) 3371, 2934, 1513, 1235. Anal. Calcd for C12H19NO2·0.33H2O: C, 66.96; H, 9.21; N, 6.51. Found: C, 67.08; H, 9.45; N, 6.23. N,N-Diethyl-4-methoxyaniline (1r).11 General procedure A (145 mg, 81%), eluting with petroleum ether/ethyl acetate (20:1): colorless oil; 1H NMR (400 MHz, CDCl3) δ 6.82 (d, J = 9.0 Hz, 2H), 6.71 (d, J = 8.7 Hz, 2H), 3.75 (s, 3H), 3.25 (q, J = 7.0 Hz, 4H), 1.10 (t, J = 7.0 Hz, 6H); 13C NMR (100 MHz, CDCl3) δ 151.6, 142.9, 115.3, 114.8, 55.8, 45.4, 12.5. N,N-Dibutyl-4-methoxyaniline (1s).35 General procedure A (202 mg, 86%), general procedure B (113 mg, 48%) general procedure E (183 mg, 78%), general procedure F (192 mg, 82%), eluting with petroleum ether: colorless oil; 1H NMR (400 MHz, CDCl3) δ 6.86− 6.77 (m, 2H), 6.70−6.60 (m, 2H), 3.76 (s, 3H), 3.21−3.13 (m, 4H), 1.59−1.45 (m, 4H), 1.38−1.25 (m, 4H), 0.93 (t, J = 7.1 Hz, 6H); 13C 5422

DOI: 10.1021/acs.joc.7b00290 J. Org. Chem. 2017, 82, 5416−5423

Note

The Journal of Organic Chemistry residue was purified using flash column chromatography on silica gel eluting with petroleum ether/ethyl acetate (20:1) to afford 10Hphenothiazine (139 mg, 70%).

■

(14) Zhu, X.; Su, L.; Huang, L.; Chen, G.; Wang, J.; Song, H.; Wan, Y. Eur. J. Org. Chem. 2009, 635−642. (15) (a) Huang, M.; Hou, J.; Yang, R.; Zhang, L.; Zhu, X.; Wan, Y. Synthesis 2014, 46, 3356−3364. (b) Meng, F.; Wang, C.; Xie, J.; Zhu, X.; Wan, Y. Appl. Organomet. Chem. 2011, 25, 341−347. (c) Xie, J.; Zhu, X.; Huang, M.; Meng, F.; Chen, W.; Wan, Y. Eur. J. Org. Chem. 2010, 2010, 3219−3223. (16) Zhang, Y.; Yang, X.; Yao, Q.; Ma, D. Org. Lett. 2012, 14, 3056− 3059. (17) Casitas, A.; Ribas, X. Chem. Sci. 2013, 4, 2301−2318. (18) (a) Creutz, S. E.; Lotito, K. J.; Fu, G. C.; Peters, J. C. Science 2012, 338, 647−651. (b) Giri, R.; Hartwig, J. F. J. Am. Chem. Soc. 2010, 132, 15860−15863. (c) Tye, J. W.; Weng, Z.; Johns, A. M.; Incarvito, C. D.; Hartwig, J. F. J. Am. Chem. Soc. 2008, 130, 9971− 9983. (19) Huang, L.; Yu, R.; Zhu, X.; Wan, Y. Tetrahedron 2013, 69, 8974−8977. (20) Dhayalan, V.; Samann, C.; Knochel, P. Chem. Commun. 2015, 51, 3239−3242. (21) Yang, B.; Mao, Z.; Zhu, X.; Wan, Y. Catal. Commun. 2015, 60, 92−95. (22) Halder, M.; Islam, M. M.; Ansari, Z.; Ahammed, S.; Sen, K.; Islam, S. M. ACS Sustainable Chem. Eng. 2017, 5, 648−657. (23) Weinmayr, V. J. Am. Chem. Soc. 1955, 77, 1762−1764. (24) Raders, S. M.; Moore, J. N.; Parks, J. K.; Miller, A. D.; Leissing, T. M.; Kelley, S. P.; Rogers, R. D.; Shaughnessy, K. H. J. Org. Chem. 2013, 78, 4649−4664. (25) Yang, C. T.; Fu, Y.; Huang, Y. B.; Yi, J.; Guo, Q. X.; Liu, L. Angew. Chem., Int. Ed. 2009, 48, 7398−7401. (26) Wei, Z.; Li, J.; Wang, N.; Zhang, Q.; Shi, D.; Sun, K. Tetrahedron 2014, 70, 1395−1400. (27) Hollmann, D.; Bähn, S.; Tillack, A.; Parton, R.; Altink, R.; Beller, M. Tetrahedron Lett. 2008, 49, 5742−5745. (28) Liu, F.; Zhu, Y. R.; Song, L. G.; Lu, J. M. Org. Biomol. Chem. 2016, 14, 2563−2571. (29) Ackermann, L.; Born, R. Angew. Chem., Int. Ed. 2005, 44, 2444− 2447. (30) Maiti, D.; Fors, B. P.; Henderson, J. L.; Nakamura, Y.; Buchwald, S. L. Chem. Sci. 2011, 2, 57−68. (31) Castillo, J.-C.; Orrego-Hernández, J.; Portilla, J. Eur. J. Org. Chem. 2016, 2016, 3824−3835. (32) Zhang, Y.; Yang, X.; Yao, Q.; Ma, D. Org. Lett. 2012, 14, 3056− 3059. (33) Mitsunaga, S.; Ohbayashi, T.; Sugiyama, S.; Saitou, T.; Tadokoro, M.; Satoh, T. Tetrahedron: Asymmetry 2009, 20, 1697− 1708. (34) Lacroix, S. D.; Pennycook, A.; Liu, S. F.; Eisenhart, T. T.; Marr, A. C. Catal. Sci. Technol. 2012, 2, 288−290. (35) Barker, T. J.; Jarvo, E. R. Angew. Chem., Int. Ed. 2011, 50, 8325− 8328. (36) Roiban, G.-D.; Mehler, G.; Reetz, M. T. Eur. J. Org. Chem. 2014, 2014, 2070−2076.

ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.joc.7b00290. 1 H NMR, 13C NMR, IR, and MS spectra for new compounds; 1H NMR, 13C NMR spectra for known compounds (PDF) X-ray crystallographic data for L3 (CIF) X-ray crystallographic data for B (CIF)

■

AUTHOR INFORMATION

Corresponding Authors

*E-mail: [email protected]. *E-mail: [email protected]. ORCID

Yiqian Wan: 0000-0002-9591-9022 Notes

The authors declare no competing financial interest.

■

ACKNOWLEDGMENTS This work was supported financially by grants from the National Natural Science Foundation of China (21272287, 21272282).

■

REFERENCES

(1) (a) Travis, A. S. Manufacture and Uses of the Anilines: A Vast Array of Processes and Products. In The Chemistry of Anilines; John Wiley & Sons, Ltd.: Chichester,, 2007. (b) Magano, J.; Dunetz, J. R. Chem. Rev. 2011, 111, 2177−2250. (c) Aubin, Y.; Fischmeister, C.; Thomas, C. M.; Renaud, J. L. Chem. Soc. Rev. 2010, 39, 4130−4145. (2) (a) Jiang, Y.; Ma, D. Assembly of N-Containing Heterocycles via Pd- and Cu-Catalyzed C−N Bond formation Reaction. In Amination and Formation of sp2 C−N Bonds; Springer-Verlag: Berlin, 2013. (b) Monnier, F.; Taillefer, M. Copper-Catalyzed C(aryl)−N Bond Formation. In Amination and Formation of sp2 C−N Bonds; SpringerVerlag: Berlin, 2013. (c) Ley, S. V.; Thomas, A. W. Angew. Chem., Int. Ed. 2003, 42, 5400−5449. (3) (a) Ma, D.; Geng, Q.; Zhang, H.; Jiang, Y. Angew. Chem., Int. Ed. 2010, 49, 1291−1294. (b) Monnier, F.; Taillefer, M. Angew. Chem., Int. Ed. 2009, 48, 6954−6971. (c) Klapars, A.; Antilla, J. C.; Huang, X.; Buchwald, S. L. J. Am. Chem. Soc. 2001, 123, 7727−7729. (4) (a) Zhou, W.; Fan, M.; Yin, J.; Jiang, Y.; Ma, D. J. Am. Chem. Soc. 2015, 137, 11942−11945. (b) Huang, M.; Lin, X.; Zhu, X.; Peng, W.; Xie, J.; Wan, Y. Eur. J. Org. Chem. 2011, 2011, 4523−4527. (5) Xie, R.; Fu, H.; Ling, Y. Chem. Commun. 2011, 47, 8976−8978. (6) Brahmachari, G. Room Temperature Organic Synthesis; Elsevier, 2015. (7) Shafir, A.; Buchwald, S. L. J. Am. Chem. Soc. 2006, 128, 8742− 8743. (8) Jiang, D.; Fu, H.; Jiang, Y.; Zhao, Y. J. Org. Chem. 2007, 72, 672− 674. (9) Tao, C.-Z.; Liu, W.-W.; Sun, J.-Y.; Cao, Z.-L.; Li, H.; Zhang, Y.-F. Synthesis 2010, 2010, 1280−1284. (10) Wang, Y.; Ling, J.; Zhang, Y.; Zhang, A.; Yao, Q. Eur. J. Org. Chem. 2015, 2015, 4153−4161. (11) Deldaele, C.; Evano, G. ChemCatChem 2016, 8, 1319−1328. (12) Yang, C.-T.; Fu, Y.; Huang, Y.-B.; Yi, J.; Guo, Q.-X.; Liu, L. Angew. Chem., Int. Ed. 2009, 48, 7398−7401 (S7398/7391-S7398/ 7182). (13) Huang, Y.-B.; Yang, C.-T.; Yi, J.; Deng, X.-J.; Fu, Y.; Liu, L. J. Org. Chem. 2011, 76, 800−810. 5423

DOI: 10.1021/acs.joc.7b00290 J. Org. Chem. 2017, 82, 5416−5423