Discrepancies between chiroptical data from the literature and our determination of the structure of the title compounds (+)-5 and (+)-9a were resolved by an unambiguous assignment of their absolute configuration. Accordingly, the dextrorotatory cis-3-hydroxy esters have (3R,4R)- and the laevorotatory enantiomers (3S,4S)-configuration. The final evidences were demonstrated on both enantiomers (+)- and
通过明确分配其绝对构型,可解决文献中的手性数据与我们对标题化合物(+)- 5和(+)- 9a的结构确定之间的差异。因此,右旋顺式-3-羟基酯具有(3 R,4 R)-和laororotatory对映异构体(3 S,4 S)-构型。面包酵母通过
生物还原4和立体选择性[Ru II(binap)]催化4的氢化反应,证明了对映体(+)-和(-)- 5的最终证据(方案2),通过在(+)-和(-)- 5(方案3)上应用NMR Mosher方法,以及通过将(+)- 5转化为共同的导数和手性相关性(方案4)。