title: Highly Z-selective asymmetric 1,4-addition reaction of 5H-oxazol-4-ones with alkynyl carbonyl compounds catalyzed by chiral guanidines.
abstract: An asymmetric 1,4-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 γ-butenolide ester bearing a chiral quaternary stereogenic center.
authors: Graduate School of Material Science, University of Hyogo, 3-2-1 Kohto, Kamigori, Hyogo 678-1297, Japan. misaki@sci.u-hyogo.ac.jp
authors: Tomonori
authors: T
authors: Misaki
authors: Kei
authors: K
authors: Kawano
authors: Takashi
authors: T
authors: Sugimura