Enantioselective Synthesis of Polysubstituted Spiro-nitroprolinates Mediated by a (R,R)-Me-DuPhos·AgF-Catalyzed 1,3-Dipolar Cycloaddition

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• 作者：Alberto Cayuelas ; Ricardo Ortiz ; Carmen Nájera ; José M. Sansano ; Olatz Larrañaga ; Abel de Cózar ; Fernando P. Cossío
• 刊名：Organic Letters
• 出版年：2016
• 出版时间：June 17, 2016
• 年：2016
• 卷：18
• 期：12
• 页码：2926-2929
• 全文大小：305K
• 年卷期：0
• ISSN：1523-7052

文摘

The synthesis of constrained spirocycles is achieved effectively by means of 1,3-dipolar cyclodditions employing α-imino γ-lactones as azomethine ylide precursors and nitroalkenes as dipolarophiles. The complex formed by (R,R)-Me-DuPhos <b>18b> and AgF is the most efficient bifunctional catalyst. Final spiro-nitroprolinates cycloadducts are obtained in good to moderate yields and both high diastereo- and enantioselectivities. Density functional theory (DFT) calculations supported the expected absolute configuration as well as other stereochemical parameters.