Asymmetric Synthesis of Vitamin D3 Analogues: Organocatalytic Desymmetrization Approach toward the A-Ring Precursor of Calcifediol

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• 作者：Haifeng Wang ; Linjie Yan ; Yan Wu ; Yipei Lu ; Fener Chen
• 刊名：Organic Letters
• 出版年：2015
• 出版时间：November 6, 2015
• 年：2015
• 卷：17
• 期：21
• 页码：5452-5455
• 全文大小：301K
• ISSN：1523-7052

文摘

A novel asymmetric synthesis has been developed for the construction of the A-ring of a chiral precursor to calcifediol. The highlights of this synthesis include (i) the introduction of the stereochemistry at the C5-position of the A-ring through the organocatalytic enantioselective desymmetrization of a prochiral cyclic anhydride using a bifunctional urea catalyst and (ii) the introduction of the exo-cyclic (Z)-dienol side chain by a tandem Claisen rearrangement/sulfoxide thermolysis of an allylic alcohol.