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.
A palladium-catalyzed construction of enantiomerically pure α-methylene-γ-butyrolactones. Enantiospecific synthesis of both enantiomers of methylenolactocin
作者:Guoxin Zhu、Xiyan Lu
DOI:10.1016/0957-4166(95)00096-8
日期:1995.4
Opticallyactive β,γ-disubstituted-α-methylene-γ-butyrolactones were synthesized by palladium(II)-catalyzed cyclization reactions of homochiral allylic 2-alkynoates. The reaction was applied to the totalsynthesis of methylenolactocin in both enantiomeric forms.