摘要:
A process for stereoselective synthesis of a compound of Formula (X) or Formula (X′) wherein: R1 is an aryl group substituted with one to three substituent groups, wherein each substituent group of R1 is independently C1-C5 alkyl, C2-C5 alkenyl, C2-C5 alkynyl, C1-C5 alkoxy, C1-C5 alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, C1-C5 alkoxycarbonylamino, aminosulfonyl, C1-C5 alkylaminosulfonyl, C1-C5 dialkylaminosulfonyl, halogen, hydroxy, carboxy, cyano, trifluoromethyl, trifluoromethoxy, nitro, or C1-C5 alkylthio wherein the sulfur atom is oxidized to sulfoxide or sulfone, and R2 and R3 are each independently hydrogen or C1-C5 alkyl.