Three of the four possible diastereoisomeric thia-Michael addition products of the reaction of methyl (5-methylidene-4-oxo-cyclopent-2-en-1-yl)acetate with ethanethiol have been isolated and characterized. The major diastereoisomer is all-trans, while the overall fraction of the minor cis,trans and trans,cis isomers does not exceed 30%. The diastereoisomer structure has been determined on the basis
(5-亚甲基-4-氧代-环戊-2-烯-1-基)
乙酸甲酯与
乙硫醇反应的四种可能的非对映异构体thia-Michael加成产物中的三种已被分离和表征。主要的非对映异构体是全反式的,而次要的顺式,反式和反式,顺式异构体的总比例不超过30%。非对映异构体结构是根据1 H NMR光谱中
环戊烷环的CH质子的特征偶合常数确定的。