Triphosgene → methyl (2S)-2-isocyanato-3,3-dimethylbutanoate

Participants

Reaction Steps

A solution (0.39 M) of methyl 3-methyl-L-valinate in a 2:1 mixture of saturated aqueous NaHCO3 and CH2Cl2 was cooled in an ice bath and stirred rapidly. The mixture was treated with triphosgene (0.45 eq) in one portion, and the resulting mixture was stirred for 0.5 h. The reaction was diluted with CH2Cl2, and the layers were separated. The aqueous phase was extracted with CH2Cl2, then the combined organics were washed with brine and dried. Removal of the solvent gave the title compound as clear oil that was kept for 12 h under vacuum (0.1 mbar) then used directly in the subsequent step. 1H NMR (400 MHz, CDCl3) δ 3.79 (s, 3H), 3.75 (s, 1H), 1.00 (s, 9H).

Provenance & Evidence