(6)(diastereoisomeric excess > 99%cis; enantiomeric excess, e.e., 80%); subsequent hydrolysis and crystallisation gives (+)-cis-(2R,3S)-3-hydroxyproline (7)(93% e.e.) which has been homologated to the bicyclic lactones (10) and (11), precursors of (–)-retronecine, (+)-platynecine, (–)-croalbinecine and related pyrrolizidines.
酵母还原酮脯
氨酸(5)得到羟基脯
氨酸衍
生物(6)(非对映异构体过量> 99%顺式;对映异构体过量,ee,80%);和(对映体过量,ee,80%)。随后
水解和结晶,得到(+)-顺式-(2 R,3 S)-
3-羟基脯氨酸(7)(93%ee),已与(-)的前体双环内酯(10)和(11)同源。 )-
维甲酸,(+)-
铂亚胺,(-)-croalbinecine和相关的
吡咯嗪核苷。