Methyl iodide → Tert-butyl allyl(but-2-yn-1-yl)carbamate

Participants

Reaction Steps

A 2.5 M hexane solution of n-butyllithium (40.8 mL, 102 mmol) was added dropwise over 30 min to a solution of tert-butyl allyl(prop-2-ynyl)carbamate (17.3 g, 89 mmol) in tetrahydrofuran (100 mL) at −10° C. After 5 min at −10° C., hexamethyl phosphoramide (17.73 mL, 102 mmol) and iodomethane (7.20 mL, 115 mmol) were added sequentially. The resultant mixture was stirred at −10° C. for 1 h, at ambient temperature for 1 h and quenched with saturated ammonium chloride (50 mL). After evaporation of the tetrahydrofuran solvent in vacuo, the residue was diluted with ethyl acetate (400 mL), washed with water, brine, dried (MgSO4) and concentrated. Silica gel chromatography, eluting with 0-100% dichloromethane in hexanes, gave tert-butyl allyl(but-2-yn-1-yl)carbamate (14.1 g, 76% yield). 1H NMR (400 MHz, chloroform-d) δ ppm 5.62-5.92 (1 H, m), 4.93-5.40 (2 H, m), 3.63-4.11 (4 H, m), 1.81 (3 H, s), 1.48 (9 H, s).

Provenance & Evidence