Methyl iodide → (3R,4S)-3-butyl-3-methyl-4-pentyloxetan-2-one

Participants

Reaction Conditions

Reaction Steps

A solution of β-lactone 3a (36.3 mg, 0.1835 mmol) in 1.9 mL THF was cooled to −78° C. and 370 μL of LiHMDS (0.367 mmol, 2.0 equiv, 1.0 M solution in THF) was added under a nitrogen atmosphere. After 1.5 h, 23 μL (0.367 mmol, 2.0 equiv) of iodomethane was added and the reaction warmed to −40° C. and stirred for an additional 45 min. The reaction mixture was concentrated in vacuo and purified by flash chromatography (0→15% Et2O: hexanes) to give β-lactone 8a (28.4 mg, 73%) as a colorless oil and as a mixture of cis/trans diastereomers (dr, 6:1). Data provided for major diastereomer: Rf(15% Et2O:hexanes) 0.64; IR (thin film) 1824 cm−1; 1H NMR (500 MHz, CDCl3) δ 4.18 (dd (major diast.), J=6.0, 8.5Hz, 1H), 1.63-1.78 (m, 2H), 1.45-1.53 (m, 2H), 1.39 (s, 3H), 1.24-1.39 (m, 10H), 0.89-0.94 (m, 6H); 13C NMR (500 MHz, CDCl3) 14.1, 14.2, 20.0, 22.1, 25.5, 25.6, 26.5, 30.3, 31.7, 35.9, 56.8, 84.5, 175.5; ESI LRMS Calcd. for C13H24O2Li [M+Li]: 219. Found: 219.

Provenance & Evidence