Total synthesis of a second generation HIV protease inhibitor

An efficient stereoselective preparation of HIV protease inhibitor (+)-1 was synthesized on multi-kilogram scale in 16 steps without the use of chromatography. The key steps include the diastereoselective alkylation of acetal 3, a diastereoselective iodo-hydroxylation to generate epoxide 6, and a reductive amination in the final coupling step that averts a non-productive cyclic aminal intermediate.