Highly<i>Z</i>-Selective Asymmetric 1,4-Addition Reaction of 5<i>H</i>-Oxazol-4-ones with Alkynyl Carbonyl Compounds Catalyzed by Chiral Guanidines
作者:Tomonori Misaki、Kei Kawano、Takashi Sugimura
DOI:10.1021/ja200283n
日期:2011.4.20
An asymmetric I,4-addition reaction of 5H-oxazol-4-ones with alkynyl carbonyl compounds was developed, and, for the first time, high enantiomeric and geometric control was achieved to afford the thermodynamically unstable Z-isomer predominantly using chiral guanidine catalysts bearing a hydroxy group at the appropriate position. The method provides synthetically useful gamma-butenolide ester bearing a chiral quaternary stereogenic center.