Stereospecific approach to the synthesis of ring-A oxygenated sarpagine indole alkaloids. Total synthesis of the dimeric indole alkaloid P-(+)-dispegatrine and six …

…, RV Edwankar, OA Namjoshi, X Liao…

Index: Edwankar, Chitra R.; Edwankar, Rahul V.; Namjoshi, Ojas A.; Liao, Xuebin; Cook, James M. Journal of Organic Chemistry, 2013 , vol. 78, # 13 p. 6471 - 6487

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Citation Number: 25

Abstract

The first regio-and stereocontrolled total synthesis of the bisphenolic, bisquaternary alkaloid (+)-dispegatrine (1) has been accomplished in an overall yield of 8.3%(12 reaction vessels) from 5-methoxy-d-tryptophan ethyl ester (17). A crucial late-stage thallium (III) mediated intermolecular oxidative dehydrodimerization was employed in the formation of the C9– C9′ biaryl axis in 1. The complete stereocontrol observed in this key biaryl coupling step ...