Transition-Metal-Free Suzuki–Miyaura Coupling Reaction of Arylpropar­gylic Bromides with Aryl- and Alkenylboronic Acids

Abstract

In the absence of transition-metal catalyst, Suzuki–Miyaura coupling reaction between aryl- and alkenylboronic acids and arylpropargylic bromides proceeded to give the corresponding acetylenic products selectively.

Key words

regioselective - propargylation - transition-metal-free - C–C bond formation - aryl- and vinylboronic acids

• References and Notes


For recent reviews, see:
• 1a Suzuki A. Angew. Chem. Int. Ed. 2011; 50: 6722
• 1b Jana R, Pathak TP, Sigman MS. Chem. Rev. 2011; 111: 1417
• 1c Heravi MM, Hashemi E. Tetrahedron 2012; 68: 9145
• 1d Johansson Seechurn CC. C, Kitching MO, Colacot TJ, Snieckus V. Angew. Chem. Int. Ed. 2012; 51: 5062
• 2 Yoshida M, Gotou T, Ihara M. Tetrahedron Lett. 2004; 45: 5573
• 3 We tested the Suzuki–Miyaura cross-coupling reaction of (3-bromoprop-1-yn-1-yl)benzene (1c) with phenylboronic acid by using Pd(PPh₃)₄ (1 mol%) and Cs₂CO₃ in toluene at 90 °C for 3 h. As the result, propargylic compound (36% yield) and allenic compound (14% yield) were obtained.
• 4a Moriya T, Miyaura N, Suzuki A. Synlett 1994; 149
• 4b Yoshida M, Ueda H, Ihara M. Tetrahedron Lett. 2005; 46: 6705
• 4c Molander GA, Sommers EM, Baker SR. J. Org. Chem. 2006; 71: 1563
• 4d Miura T, Shimada M, Mendoza P, Deutsch C, Krause N, Murakami M. J. Org. Chem. 2009; 74: 6050
• 5 Ueda M, Nishimura K, Kashima R, Ryu I. Synlett 2012; 23: 1085
• 6 Scrivanti A, Beghetto V, Bertoldini M, Matteoli U. Eur. J. Org. Chem. 2012; 264
• 7 Typical Procedure for a Metal-Catalyst-Free Suzuki–Miyaura Cross-Coupling Reaction of Propargylic Bromides with Aryl- and Alkenylboronic Acids A mixture of 1-(3-bromoprop-1-yn-1-yl)naphthalene (1e, 0.5 mmol), 4-methoxyphenylboronic acid (2a, 0.65 mmol, 1.3 equiv), Cs₂CO₃ (0.75 mmol, 1.5 equiv), and H₂O (7.8 equiv) in CHBr₃ (0.33 mL, 1.5 M for 1e) was stirred at 90 °C. After 18 h, the reaction mixture was treated with aq 1 N HCl, extracted with CH₂Cl₂, and dried over MgSO₄. The organic layer was concentrated in vacuo, and the resulting residue was purified by column chromatography on silica gel (hexane–EtOAc, 100:1) to give 1-[3-(4-methoxy)-phenylprop-1-yn-1-yl]naphthalene (3ea) as a yellow liquid (87.4 mg, 64%). ¹H NMR (500 MHz, CDCl₃): δ = 3.82 (s, 3 H), 3.94 (s, 2 H), 6.91 (d, J = 8.7 Hz, 2 H), 7.41 (m, 3 H), 7.53 (m, 2 H), 7.67 (d, J = 6.9 Hz, 1 H), 7.80 (d, J = 8.3 Hz, 1 H), 7.84 (d, J = 7.4 Hz, 1 H), 8.35 (d, J = 8.3 Hz, 1 H). ¹³C NMR (125 MHz, CDCl₃): δ = 25.2, 55.2, 80.4, 93.0, 114.0, 121.4, 125.2, 126.2, 126.5, 128.2, 128.8, 128.9, 130.2, 133.1, 133.5, 158.4. IR (neat): 3058, 2223, 1248, 1034 cm^–1. HRMS (EI): m/z calcd for C₂₀H₁₆O: 272.1201; found: 272.1200.
• 8 The reaction of isolated sodium trihydroxy(4-methoxyphenyl)borate (1.3 equiv) with 1c gave the corresponding product 3ca in 41% yield under the same conditions as shown in Table 2 without base.
• 9 Methyl ester of 2a did not work as a substrate. This result clarifies the significance of a six-membered transition state B to give the corresponding acetylenic products selectively.