Synlett 2002(1): 0146-0148
DOI: 10.1055/s-2002-19357
LETTER
© Georg Thieme Verlag Stuttgart · New York

Palladium-Catalyzed Allylic Substitution Using in Situ Generated Allylindium Reagents

Phil Ho Lee*a, Sun-young Sunga, Kooyeon Leea, Sukbok Changb
a Department of Chemistry, Kangwon National University, Chunchon 200-701, Republic of Korea
Fax: +82(33)2537582; e-Mail: phlee@kangwon.ac.kr;
b Department of Chemistry, Ewha Womans University, Seoul 120-750, Republic of Korea
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Publikationsverlauf

Received 10 October 2001
Publikationsdatum:
01. Februar 2007 (online)

Abstract

It was found that in situ generated allylindium reagent from the reaction of allyl halides with indium is the efficient nucleophile for Pd-catalyzed allylic substitution to produce 1,5-dienes in good yield.

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Representative experimental procedure: To a solution of Pd2(dba)3CHCl3 (5.2 mg, 1 mol%) and tri-o-tolylphosphine (12.2 mg, 8 mol%) in THF (1 mL) was added trans-cinnamyl methyl carbonate (96 mg, 0.5 mmol) at r.t. under a nitrogen atmosphere. After 15 min, allylindium reagent [in situ generated from allyl bromide (91 mg, 0.75 mmol) and indium (57 mg, 0.5 mmol) in THF (1 mL)] was added and the mixture was stirred at 65 °C for 24 h. The reaction mixture was quenched with saturated aqueous NaHCO3. The aqueous layer was extracted with ether (3 × 15 mL), and the combined organic layers were washed with water and brine, dried with MgSO4, filtered, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography using n-hexane to give trans-1-phenyl-1,5-hexadiene (71 mg, 90%): 1H NMR (CDCl3, 400 MHz) δ 7.34 (2 H, d, J = 7.4 Hz), 7.29 (2 H, t, J = 7.9 Hz), 7.19 (1 H, t, J = 7.1 Hz), 6.41 (1 H, d, J = 15.9 Hz), 6.23 (1 H, dt, J = 15.7, 6.6 Hz), 5.88 (1 H, tt, J = 10.4, 6.6 Hz), 5.06 (1 H, d, J = 17.2 Hz), 4.99(1 H, d, J = 9.7 Hz), 2.33-2.23 (4 H, m); 13C NMR (CDCl3, 100 MHz) δ 138.1, 137.8, 130.2, 130.1, 128.5, 126.9, 125.9, 114.9, 33.6, 32.4; HRMS (EI) calcd for C12H14 158.1096, found 158.1095.