Terminating catalytic asymmetric Heck cyclizations by stereoselective intramolecular capture of η3-allylpalladium intermediates: total synthesis of (-)-spirotryprostatin B and three stereoisomers

TETRAHEDRON

卷:66

Article; Proceedings Paper

Overman, Larry E.¹  Rosen, Mark D.¹ 

[1] Univ Calif Irvine, Dept Chem, Irvine, CA 92697 USA

关键词: Palladium catalysis;    Total synthesis;    Alkaloid;    Mechanism;    Cascade reaction;   

DOI  :  10.1016/j.tet.2010.05.048

来源: Elsevier

【 摘 要 】

A catalytic intramolecular Heck reaction, followed by capture of the resulting eta(3)-allylpalladium intermediate by a tethered diketopiperazine, is the central step in a concise synthetic route to (-)-spirotryprostatin B and three stereoisomers. This study demonstrates that an acyclic, chiral eta(3)-allylpalladium fragment generated in a catalytic asymmetric Heck cyclization can be trapped by even a weakly nucleophilic diketopiperazine more rapidly than it undergoes diastereomeric equilibration. (C) 2010 Elsevier Ltd. All rights reserved.

【 授权许可】

Free