A Dipolar Cycloaddition Approach Toward the Kopsifoline Alkaloid Framework

• Type of Material: Article
• Authors: Xuechuan Hong, Emory University; Stefan France, Emory University; Albert Padwa, Emory University
• Language: English
• Date: 2007-06-25
• Publisher: Elsevier
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2007 Elsevier Inc. All rights reserved.
• License: Creative Commons Attribution-NonCommerical-NoDerivs 3.0 Unported
• Final Published Version (URL): http://dx.doi.org/10.1016/j.tet.2007.01.064
• Title of Journal or Parent Work: Tetrahedron
• ISSN: 0040-4020
• Volume: 63
• Issue: 26
• Start Page: 5962
• End Page: 5976
• Grant/Funding Information: We greatly appreciate the financial support provided by the National Institutes of Health (GM 059384) and the National Science Foundation (Grant CHE-0132651).
• Keywords: synthesis; alkaloid; cycloaddition; indole; diazoimide; rhodium(II); kopsifoline
• Research Categories: Chemistry, Biochemistry; Chemistry, General

Abstract

Using a metal-catalyzed domino reaction as the key step, the heterocyclic skeleton of the kopsifoline alkaloid family was constructed by a 1,3-dipolar cycloaddition of a carbonyl ylide dipole derived from a Rh(II)-catalyzed reaction of a diazo ketoester across the indole π-bond. Ring opening of the resulting 1,3-dipolar cycloadduct followed by a reductive dehydroxylation step resulted in the formation of a critical silyl enol ether necessary for the final F-ring closure of the kopsifoline skeleton.