Synthesis of Leprapinic Acid, Calycine and Analogues by Sequential “[3+ 2] Cyclization/Suzuki/Lactonization” Reactions

Z Ahmed, U Albrecht, P Langer

Index: Ahmed, Zafar; Albrecht, Uwe; Langer, Peter European Journal of Organic Chemistry, 2005 , # 16 p. 3469 - 3474

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Citation Number: 10

Abstract

Abstract Calycine and analogues were prepared on the basis of Suzuki cross-coupling reactions of γ-alkylidene-α-hydroxybutenolides–readily available by cyclization of 1, 3- dicarbonyl dianions or 1, 3-bis (silyl enol ether) s with oxalyl derivatives–and subsequent boron tribromide-mediated lactonization. Leprapinic acid was prepared by chemoselective boron tribromide-mediated deprotection of permethylated leprapinic acid.(© Wiley-VCH ...