An enantioselective ring expansion route leading to furanose and pyranose nucleosides featuring spirodiketopiperazines at the anomeric position

LA Paquette, S Brand, C Behrens

Index: Paquette, Leo A.; Brand, Stephen; Behrens, Carsten Journal of Organic Chemistry, 1999 , vol. 64, # 6 p. 2010 - 2025

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Citation Number: 40

Abstract

A study directed at the enantioselective synthesis of spirodiketopiperazine homologues of hydantocidin is described. Furanoid glycals, systems that are amenable to C-5 metalation in the presence of tert-butyllithium, are readily coupled to N-protected 2, 3-azetidinediones provided that at least 1 equiv of BF3⊙ OEt2 is present to curb enolization. The resulting 1: 1 mixtures of carbinols undergo smooth ring expansion to spirocyclic keto amides when ...