Synlett 2005(12): 1877-1880  
DOI: 10.1055/s-2005-871569
LETTER
© Georg Thieme Verlag Stuttgart · New York

A Simple Synthetic Approach to Allylated Aromatics via the Suzuki-Miyaura Cross-Coupling Reaction

Sambasivarao Kotha*, Manoranjan Behera, Vrajesh R. Shah
Department of Chemistry, Indian Institute of Technology-Bombay, Powai, Mumbai - 400 076, India
Fax: +91(22)25723480; e-Mail: srk@chem.iitb.ac.in;
Further Information

Publication History

Received 20 April 2005
Publication Date:
07 July 2005 (online)

Abstract

The Pd-catalyzed cross-coupling reaction of aromatic ­iodides and bromides with allylboronic acid esters (2a,b) in the presence of CsF gave allylated aromatics.

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Representative Experimental Procedure for Cross-Coupling Reaction.
A two-neck round-bottom flask was charged diiodo compound 1 (0.049 mmol), CsF (0.19 mmol), Pd(PPh3)4 (5-10 mol%) in THF (3 mL) and stirred for 30 min. Allyl boronic acid pinacol ester 2a (0.176 mmol) in THF (3 mL) was added and the resulting reaction mixture was heated to reflux for 24 h. Then, another portion of CsF (0.19 mmol) and Pd(PPh3)4 (5-10 mol%) were added and reaction was continued. At the end of the reaction (TLC monitoring), the reaction mixture was diluted with petroleum ether (bp 60-80 °C, 10 mL) followed by H2O. The layers were separated and the aqueous layer was extracted with petroleum ether (2 × 10 mL). The combined organic layers were washed with H2O (20 mL), brine (20 mL) and dried (Na2SO4). Evaporation of the solvent gave the crude product, which was purified by silica gel column chromatography. Elution of the column with 10% EtOAc-petroleum ether gave the diallylated product 3 (90%) as a white solid which was characterized by spectral data.

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Spectral Data for Compound 3. Mp 64-68 °C. IR (neat): 3404, 1728, 1672 cm-1. 1H NMR (300 MHz, CDCl3): δ = 1.40 (t, 3 H, J = 7.4 Hz), 3.21-3.40 (m, 6 H), 3.70 (d, 2 H, J = 14.9 Hz), 4.30 (q, 2 H, J = 7.4 Hz), 5.00-5.12 (m, 4 H), 5.81-6.12 (m, 2 H), 6.22 (s, 1 H), 7.00-7.21 (m, 8 H), 8.21 (s, 1 H). 13C NMR (100 MHz, CDCl3): δ = 14.2, 39.8, 40.7, 62.2, 67.6, 115.8, 128.5, 129.8, 133.7, 137.3, 138.8, 160.8, 172.0. HRMS (FAB): m/z [M + H]+ calcd for C25H29NO3: 392.2226; found: 392.2231.

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Compounds 4, [33] 6, [34] 7, [35] 9, [36] 10, [37] 11, [38] 12 [40] are reported in literature by different routes.

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Spectral Data. Compound 5: IR (neat): 3020, 1720, 1608, 1502, 1086 cm-1. 1H NMR (300 MHz, CDCl3): δ = 3.40 (d, J = 6.5 Hz, 2 H), 3.81-3.96 (m, 6 H), 5.02-5.09 (m, 2 H), 5.91-6.00 (m, 1 H), 6.90 (d, J = 8.7 Hz, 1 H), 7.29 (s, 1 H), 7.60 (d, J = 8.7 Hz, 1 H). 13C NMR (75.4 MHz, CDCl3): δ = 39.1, 52.1, 56.2, 112.2, 116.1, 119.8, 131.7, 133.7, 137.2, 157.6, 166.8. MS (EI, Q-TOF): m/z calcd for [C12H12O3 + Na]: 229.0841; found: 229.0850.
Compound 8: IR (neat): νmax = 1736, 1657, 1268, 1157, 1052 cm-1. 1H NMR (400 MHz, CDCl3): δ = 2.51 (s, 3 H), 3.59 (d, 2 H, J = 7.6 Hz), 5.15-5.22 (m, 2 H), 5.90-6.01 (m, 1 H), 6.84 (d, 1 H, J = 4.0 Hz), 7.55 (d, 1 H, J = 3.6 Hz). 13C NMR (75.4 MHz, CDCl3): δ = 26.6, 34.9, 117.5, 126.1, 133.0, 135.2, 142.8, 152.9, 190.6. MS (EI, Q-TOF): m/z [M + H]+ calcd for C9H10OS: 167.0531; found: 167.0530.