Ethyl chloroformate → Ethyl 4-methylpent-2-ynoate

Participants

Reaction Conditions

Reaction Steps

Under an Ar atmosphere, to a mixture of 3-Methylbutyne (1.5 g, 22.0 mmol) in THF (15 ml) was added a solution of 2.5 M n-BuLi in hexanes (9.68 ml, 24.2 mmol) at −78° C. over 15 min, then the mixture was stirred at −78° C. for 5 min, and at −5˜−10° C. for 30 min. Ethyl chloroformate (2.63 g, 24.2 mmol) was added drop wise at −78° C., then the mixture was stirred at 0° C. for 1 h. The reaction was quenched with saturated aqueous NH4Cl under ice cooling, and the whole was extracted with Et2O. The organic layer was washed with brine, dried over Na2SO4, and then concentrated. Purification by kugelrohr distillation (1˜3 mmHg 70˜80° C.) gave 2b (59%). 2b: colorless oil; 1H-NMR (CDCl3) δ 1.24 (6H, d, J=7.0 Hz), 1.31 (3H, t, J=7.2 Hz), 2.70 (1H, sep, J=7.0 Hz), 4.22 (2H, q, J=7.2 Hz).

Provenance & Evidence