SYNTHESIS OF HYDROXYETHYLENE ISOSTERES OF THE TRANSITION-STATE OF THEHIV PROTEASE-CATALYZED PHE-PRO HYDROLYSIS - REACTION OF BOC)AMINO]-1-(2'-OXOCYCLOPENTYL)-3-PHENYLPROPANOLS WITH DIETHYL PHOSPHOROCYANIDATE AND LITHIUM CYANIDE FOLLOWED BY SAMARIUM IODIDE

Reaction of cyclopentanone enolate (7) with BoC-L-Phenylalaninal (6) a fforded a mixture of four aldol products 5a-d in a 3:3:1:1 ratio. Reac tion of 5a with diethyl phosphorocyanidate followed by samarium iodide reduction afforded lactone 13a and phosphate 12. The structure of 12 was confirmed by X-ray crystallography. Deprotection of 13a gave -1'-h ydroxy-3'-phenylpropyl)cyclopentanecarboxylic acid lactone (14a), whic h was transformed to a crystalline lactam 15a under basic conditions. The structure of 15a was also confirmed by X-ray analysis.