Benzyl chloroformate → (2S)-1-((benzyloxy)carbonyl)-4-hydroxypyrrolidine-2-carboxylic acid

Participants

Reaction Steps

To 20 g (152.5 mmol) of 4-hydroxy-L-proline in 35 ml of water was added 36.7 g (436.8 mmol) of sodium bicarbonate and the mixture was cooled to 10° C. before 32.5 g (190.5 mmol) of benzylchloroformate wa added dropwise. The cooling bath was then removed and the mixture was allowed to stir for 24 hours at room temperature. The pH of the reaction was then adjusted to 1 with concentrated HC1 solution and the mixture was extracted with 3 x 100 ml portions of methylene chloride. The organic layers were dried over Na2SO4 and evaporated in vacuum to provide 36.4 g of the product as an oil (90% yield). NMR(CDC13): 7.30 (m,5H, aromatic), 5.12 (m,2H), 4.50 (m,2H), 4.36 (m,2H), 3.6 (m,2H), 2.38 (m,2H).

Provenance & Evidence