1. The enantiomerically enriched compound of Formula II where A is (C-C) alkyl-O-, phenyl- (C-C) alkyl-O-； aryl selected from phenyl, naphthyl, and which is optionally substituted with 1-3 substituents, where the substituents are selected from (C-C) alkyl, (C-C) cycloalkyl, (C-C) alkyl-O-, hydroxy, amino and halogen； or heteroaryl having four or five carbon atoms and one heteroatom selected from oxygen, nitrogen and sulfur, which is optionally substituted with 1-3 substituents, where the substituents are selected from (CC) alkyl, (CC) cycloalkyl, (CC) alkyl-O- , hydroxy, amino and halogen； B is phenyl optionally substituted with 1-3 substituents, where the substituents are selected from (CC) alkyl, (CC) cycloalkyl, (CC) alkyl-O-, hydroxy, amino and halo； and R and R independently represent (CC) alkyl, phenyl- (CC) alkyl, hydroxy- (CC) alkyl, (CC) cycloalkyl, (CC) alkenyl or (CC) alkynyl； provided that R differs from R； where the absolute configuration the asymmetric carbon atom bearing R and R is preferably the S configuration； or a pharmaceutically acceptable salt thereof. 2. The compound according to claim 1, where A represents-OS (CH), -OCHPh； aryl selected from phenyl, naphthyl, and which is optionally substituted with 1-3 substituents, where the substituents are selected from (C-C) alkyl, (C-C) cycloalkyl, (C-C) alkyl-O-, hydroxy, amino and halogen； or heteroaryl having four or five carbon atoms and one heteroatom selected from oxygen, nitrogen and sulfur, which is optionally substituted with 1-3 substituents, where the substituents are selected from (CC) alkyl, (CC) cycloalkyl, (CC) alkyl-O- , hydroxy, amino and halogen； B is phenyl, optionally substituted with 1-3 substituents, where the substituents are selected from (CC) alkyl, (CC) alkyl-O- and halogen； R is (CC) alkyl, hydroxy (CC) alkyl or (CC) al1. Энантиомерно обогащенное соединение Формулы IIгдеA представляет собой (C-C)алкил-O-, фенил-(C-C)алкил-O-； арил, выбранный из фенила, нафтила,и, который возмо
