Benzyl iodide → (3R,4R)-3-Benzyl-4-isopropyl-dihydro-furan-2-one

関与物質

反応手順

Lithium bis(trimethylsilyl)amide (1.0 M solution in THF, 92 mL, 92 mmol) was added in 3-5 minutes to a solution of (S)-β-(2-propyl)-γ-butyrolactone 175 (11.68 g, 91.25 mmol) in dry THF 100 mL at −78° C. under argon atmosphere. It was stirred for 1 h and a solution of benzyl iodide (21.87 g, 100.37 mmol )in dry THF was added rapidly. Stirring was continued for 1.5 hours and quenched at −78° C. by the addition of a solution of brine followed by ethyl acetate. The organic phase was separated and the aqueous was further extracted with ether. Chromatography on silica gel first eluted with 5% methylene chloride in pet ether, and finally with 10% ether in pet ether gave desired compound 11.6 g, 58%. NMR (CDCl3) δ 7.19 (m, 5H, C6H5), 4.02 (app. t, 1H, CHaHbO), 3.87 (dd, 1H, CHaHbO), 2.98 (d, 2H, ArCH2), 2.57 (q, 1H, BnCHC═O), 2.05 (m, 1H, CHCH(Me)2, 1.55 (m, 1H, CH(Me)2), 0.81 (d, 3H, CH3) and 0.72 (d, 3H, CH3).

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