Stereoselective synthesis of enantiopure β, γ-disubstituted α-alkylideneγ-butyrolactones via A palladium(II) catalyzed cyclization
作者:Guoxin Zhu、Xiyan Lu
DOI:10.1016/0957-4166(95)00009-e
日期:1995.2
β, γ-disubstituted α-alkylidene-γ-butyrolactones with cis or trans relative configurations were synthesized in both optically active forms from readily available homochiral allylic 2-alkynoates by Pd(II) catalysis in the presence of CuX2 and LiX.
Palladium-Templated Regio- and Stereoselective Cyclization of 2'-Alkenyl 2-Alkynoates and Its Synthetic Applications
作者:Jianguo Ji、Chunming Zhang、Xiyan Lu
DOI:10.1021/jo00110a018
日期:1995.3
2'-Alkenyl 2-alkynoates undergo facile stereoselective cyclization to alpha-(haloalkylidene)-gamma-butyrolactones upon treatment with a catalytic amount of palladium complex in the presence of CuX(2) and LiX. When an alkyl group is introduced to the 1'-position of the alkenyl group, unsubstituted 2-propynoates mainly give trans-beta, gamma-disubstituted gamma-lactones, and substituted 2-propynoates afford cis-beta,gamma-disubstituted gamma-lactones. Further elaborations of the halogen atoms and the synthesis of A-factor using this method are exemplified.