作者:Rajendra P Jain、Robert M Williams
DOI:10.1016/s0040-4039(01)00780-8
日期:2001.7
TBDMS-protected hemiketal thus obtained was efficiently converted into highly enantiomerically enriched (R)-(−)-carnitine by following an elimination–reduction protocol. This approach further demonstrates the utility of commercially available glycine template 1 as a potential substrate for the asymmetric synthesis of both enantiomers of carnitine.
乙酸乙酯的烯酮甲硅烷基乙缩醛与(5 R,6 S)-4-(苄氧羰基)-5,6-二苯基-2,3,5,6-内酯羰基的TiCl 4促进的Mukaiyama型醛醇缩合反应四氢-4 H -1,4-恶嗪-2-酮(1)的非对映选择性很高。通过遵循消除-减少方案,将如此获得的TBDMS保护的半缩酮有效地转化为高度对映体富集的(R)-(-)-肉碱。该方法进一步证明了可商购的甘氨酸模板1作为肉碱的两种对映异构体不对称合成的潜在底物的实用性。