Synthesis of the bis-spiroacetal moiety of the polyether antibiotic CP44, 161

PR Allen, MA Brimble, H Prabaharan

Index: Allen, Paul R.; Brimble, Margaret A.; Prabaharan, Hishani Journal of the Chemical Society. Perkin Transactions 1, 2001 , # 4 p. 379 - 389

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Citation Number: 10

Abstract

The syntheses of bis-spiroacetals 25a, 25c and 40 which constitute the central framework of the polyether antibiotic CP44, 161 4, are described. The tricyclic bis-spiroacetal ring is formed by oxidative cyclisation of hydroxyspiroacetal 9 which in turn is assembled from lactone 10 and acetylene 11. The key stereogenic centres in acetylene 11 were assembled using a Sharpless asymmetric dihydroxylation and an Evans asymmetric alkylation of a ...