Approach to the homoerythrina alkaloids using a tandem N-alkylation/azomethine ylide cycloaddition

WH Pearson, JE Kropf, AL Choy, IY Lee…

Index: Pearson, William H.; Kropf, Jeffrey E.; Choy, Allison L.; Ill, Young Lee; Kampf, Jeff W. Journal of Organic Chemistry, 2007 , vol. 72, # 11 p. 4135 - 4148

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Citation Number: 32

Abstract

Synthetic efforts toward the homoerythrina alkaloids 1-3 are described. Two separate model systems guided the pivotal [3+ 2] azomethine ylide cycloaddition cascade to form the AC rings of these alkaloids. The cycloaddition precursors 63 and 68, prepared in nine and ten steps, respectively, from alkyne 47, each contain an enolizable ketone, a tethered electrophile, and an electron-poor dipolarophile. Heating 63 and 68 with the stannyl ...