Aziridine-Allylsilane-Mediated Total Synthesis of (-)-Yohimbane

Stephen C. Bergmeier; Punit P. Seth

doi:10.1021/jo9825097

Aziridine-Allylsilane-Mediated Total Synthesis of (-)-Yohimbane

J Org Chem. 1999 Apr 30;64(9):3237-3243. doi: 10.1021/jo9825097.

Authors

Stephen C. Bergmeier¹, Punit P. Seth

Affiliation

¹ Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy and the Comprehensive Cancer Center, The Ohio State University, 500 West 12th Avenue, Columbus, Ohio 43210-1291.

PMID: 11674426
DOI: 10.1021/jo9825097

Abstract

A total asymmetric synthesis of (-)-yohimbane and ent-alloyohimbane is reported. The synthesis utilizes a novel aziridine-allylsilane cyclization reaction as a key step in the synthesis. Treatment of optically pure aziridine-allylsilane 16 with BF(3).OEt(2) provided a mixture of aminomethyl substituted carbocycles trans-20a and cis-20b in excellent yield and modest diastereoselectivity (trans/cis 3:1). Alkylation of the tosylamide followed by oxidation of the olefin in 20 provided the lactam 38, which was converted to (-)-yohimbane and ent-alloyohimbane by a Bischler-Napieralski reaction. The synthesis provided (-)-yohimbane in eight steps and 24% overall yield (from 16).