The lithihum (a-carbalkoxyvinyl) (2-thienyl) mixed higher order cyanocuprate, de-rived from ethyl propargylic ester with (n-C13H27) (2-thienyl)CuCNLi2, reacted with cis-1-bromo-l-propylene under Pd (PPh3)4 catalysis t...The lithihum (a-carbalkoxyvinyl) (2-thienyl) mixed higher order cyanocuprate, de-rived from ethyl propargylic ester with (n-C13H27) (2-thienyl)CuCNLi2, reacted with cis-1-bromo-l-propylene under Pd (PPh3)4 catalysis to give a diene ester ethyl 1- (Z-propylidene)-1-E-hexadecenate. Then the target product (±)-litsenolide C2 was stereoselectively synthe-sized by employing cis-dihydroxylation of the diene ester using a NMO-OsO4 system as the oxidant and stereospecific lactonation by acidic catalyst. The ratio of E to Z carbon-carbon double bond is >98: 2, and the ratio of trans- and cis-disubstituted lactones is >95: 5.展开更多
文摘The lithihum (a-carbalkoxyvinyl) (2-thienyl) mixed higher order cyanocuprate, de-rived from ethyl propargylic ester with (n-C13H27) (2-thienyl)CuCNLi2, reacted with cis-1-bromo-l-propylene under Pd (PPh3)4 catalysis to give a diene ester ethyl 1- (Z-propylidene)-1-E-hexadecenate. Then the target product (±)-litsenolide C2 was stereoselectively synthe-sized by employing cis-dihydroxylation of the diene ester using a NMO-OsO4 system as the oxidant and stereospecific lactonation by acidic catalyst. The ratio of E to Z carbon-carbon double bond is >98: 2, and the ratio of trans- and cis-disubstituted lactones is >95: 5.
