Brønsted Base and Lewis Acid Cooperatively Catalyzed Asymmetric <i>exo</i>′-Selective [3 + 2] Cycloaddition of Trifluoromethylated Azomethine Ylides and Methyleneindolinones
Yi Yang, Yuan‐Zhao Hua, Huijie Lü, Lantao Liu, Min‐Can Wang
Abstract
A Brønsted base and Lewis acid cooperatively catalyzed 1,3-dipolar cycloaddition is reported through chiral dinuclear zinc catalysts. An asymmetric exo′-selective [3 + 2] cycloaddition of CF3-containing N-unprotected isatin-derived azomethine ylides is realized. In the presence of 10 mol % of catalyst, azomethine ylides react efficiently with methyleneindolinones, giving a series of trifluoromethyl-substituted 2,3-pyrrolidinyl dispirooxindoles with highly enantio- (up to 99% ee) and exo′-selectivity (>20:1 dr). Up to four contiguous stereogenic centers, including two adjacent spiro quaternary stereocenters, are constructed in one step.
Topics & Concepts
ChemistryCycloadditionCatalysisLewis acids and basesAzomethine ylideBrønsted–Lowry acid–base theoryBase (topology)Medicinal chemistryOrganocatalysisCombinatorial chemistryStereochemistryEnantioselective synthesisOrganic chemistry1,3-Dipolar cycloadditionMathematical analysisMathematicsFluorine in Organic ChemistrySynthesis and Catalytic ReactionsCyclopropane Reaction Mechanisms