Enantioselective total syntheses of pumiliotoxin B and pumiliotoxin 251D. A general entry to the pumiliotoxin A alkaloids via stereospecific iminium ion-vinylsilane cyclizations
Enantioselective total syntheses of pumiliotoxin B and pumiliotoxin 251D. A general entry to the pumiliotoxin A alkaloids via stereospecific iminium ion-vinylsilane cyclizations
[reaction: see text] A convergent enantioselective synthesis of the natural product (-)-callystatin A (1) is described. Key features of the synthesis include a lipase-mediated kinetic resolution to install the C5 lactone stereochemistry, a hydrozirconation-based approach to the C8-C9 trisubstituted (Z)-olefin, and a stereoselective cross-coupling of a vinyl dibromide to install the C14-C15 trisubstituted
Stereoselective Synthesis of Functionalized Trisubstituted Olefins via Palladium(0)-Catalyzed Cross-Coupling Reaction
作者:Alexander Arefolov、Neil F. Langille、James S. Panek
DOI:10.1021/ol016486l
日期:2001.10.1
[reaction: see text]. A highly flexible and stereoselective protocol for the synthesis of branched (E)- and (Z)-trisubstituted alkenes has been developed. The key steps are hydrozirconation-iodination of (1-alkynyl)trimethylsilane followed by Negishi-type cross-coupling. The resultant (Z)-vinyl silane is iododesilylated and subjected to a second cross-couplingreaction to give the trisubstituted olefin
Enantioselective total syntheses of pumiliotoxin B and pumiliotoxin 251D. A general entry to the pumiliotoxin A alkaloids via stereospecific iminium ion-vinylsilane cyclizations