A formal synthesis of (+)-lactacystin has been completed from trans-4-hydroxyproline, using a diastereoselective enolate acylation reaction as a key step. Diastereoselectivity was seen to vary as a function of the steric bulk of the C4-O-protecting group, and contrary to expectations, the best diastereoselectivities were obtained when the small methyl carbonate protecting group was used. The formal synthesis was then completed by intercepting ...
