About this item:

522 Views | 0 Downloads

Author Notes:

chemap@emory.edu

Subject:

Research Funding:

This research was supported by the National Institutes of Health (GM 0539384) and the National Science Foundation (CHE-0450779).

Application of the Aza-Achmatowicz Oxidative Rearrangement for the Stereoselective Synthesis of the Cassia and Prosopis Alkaloid Family

Tools:

Journal Title:

Journal of Organic Chemistry Research

Volume:

Volume 71, Number 22

Publisher:

, Pages 8591-8601

Type of Work:

Article | Post-print: After Peer Review

Abstract:

cis-2-Methyl-6-substituted piperidin-3-ol alkaloids of the Cassia and Prosopis species are readily prepared by a combination of an aza-Achmatowicz oxidative rearrangement, dihydropyridone reduction followed by a Stereoselective allylsilane addition to a N-sulfonyliminium ion. The stereochemical outcome of the reduction reaction can be attributed to steric hindrance between the pseudoaxially oriented 2,6-substituents and the equatorially approaching hydride reagent which explains the exclusive formation of the cis-alcohol by axial approach of the hydride. The unsaturation present in the (E)-methyl-pent-3-enoate side chain was removed by catalytic reduction and the remaining ester group was converted to the corresponding Weinreb’s amide. This key intermediate was utilized for the synthesis of azimic acid, deoxocassine, cassine and spicigerine. The facile preparation of (S)-N-tosylamidofuran 16 and its conversion to the chiral Achmatowicz oxidation product 18 provides a formal chiral synthesis of these alkaloids.

Copyright information:

© 2006 American Chemical Society

Export to EndNote