Regio- and enantioselective synthesis of allenic esters by samarium(II)-mediated reduction of propargylic compounds through dynamic kinetic protonation
作者:Koichi Mikami、Akihiro Yoshida
DOI:10.1016/s0040-4020(00)01044-9
日期:2001.1
Regioselective synthesis of allenic esters was attained by SmI2-mediated reduction of propargylic phosphates and ethers bearing alkoxycarbonyl groups at the acetylene terminus. Using suitable chiral proton source in this system, highly enantio-enriched allenic ester was obtained through dynamic kinetic resolution by Lewis acidic Sm(III)-mediated enantioselective protonation, even if starting with racemic
Catalytic asymmetric carbonyl-ene reactions with alkynylogous and vinylogous glyoxylates: Application to controlled synthesis of chiral isocarbacyclin analogues
The asymmetriccarbonyl-enereaction with alkynylogous and vinylogous glyoxylates (I, 2) catalyzed by a binaphthol-derivedchiraltitaniumcomplex is described. The catalytic asymmetric ene reaction with aldehyde (1) can be applied to the double asymmetric synthesis of isocarbacyclin analogues bearing a 2-allenyl side chain.