exo- and enantioselective cycloaddition of azomethine ylides generated from N-alkylidene glycine esters using chiral phosphine-copper complexes.
High diastereo- and enantioselectivities were obtained for the asymmetric 1,3-dipolar cycloaddition of azomethine ylides generated from N-alkylideneglycine esters with dipolarophiles using chiral phosphine-copper complexes as catalysts. Whereas the cycloaddition of azomethine ylides catalyzed by metal salts generally afforded endo-adducts as the predominant product, the present method is the first example of an exo-selective cycloaddition. [reaction: see text]
Oderaotoshi
Yoji
Y
Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka 565-0871, Japan.
Cheng
Wenji
W
Fujitomi
Shintaro
S
Kasano
Yukihiro
Y
Minakata
Satoshi
S
Komatsu
Mitsuo
M