Synthesis of Bicyclic Pyroglutamic Acid Featuring the Ugi Reaction and a Unique Stereoisomerization at the Angular Position by Grob Fragmentation Followed by a Transannular Ketene [2+2] Cycloaddition Reaction
Scalable Preparation of Both Enantiomers of 2-(1-Hydroxy-2-oxocyclohexyl)acetic Acid
作者:Mitchell Vamos、Yoshihisa Kobayashi
DOI:10.1021/jo8000904
日期:2008.5.1
The efficient, scalable preparation of both enantiomers of 2-(1-hydroxy-2-oxocyclohexyl)acetic acid in enantiomerically pure form is reported using environmentally benign conditions in 30% overall yield (6 steps) for the (S)-isomer, in 27% (7 steps) for the (R)-isomer, from cyclohexanone.
Mondon,A. et al., Chemische Berichte, 1963, vol. 96, p. 826 - 839
作者:Mondon,A. et al.
DOI:——
日期:——
Synthesis of Bicyclic Pyroglutamic Acid Featuring the Ugi Reaction and a Unique Stereoisomerization at the Angular Position by Grob Fragmentation Followed by a Transannular Ketene [2+2] Cycloaddition Reaction
A stereoisomerization at the angular position of N-acylindoles during basic hydrolysis was discovered to give only the syn-bicyclic pyroglutamic acid, proceeding through a transannular [2+2] cycloaddition of a ketene-ketone intermediate generated by a Grob fragmentation.