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Highly Enantioselective Copper(I)−Fesulphos-Catalyzed 1,3-Dipolar Cycloaddition of Azomethine Ylides

2005; American Chemical Society; Volume: 127; Issue: 47 Linguagem: Inglês

10.1021/ja0552186

1943-2984

Silvia Cabrera, Ramón Goméz Arrayás, Juan C. Carretero,

Asymmetric Synthesis and Catalysis

The catalyst system formed by Cu(CH3CN)4ClO4 and the planar chiral P,S-ligand Fesulphos behaves as a very efficient chiral Lewis acid in the catalytic asymmetric 1,3-dipolar cycloaddition of azomethine ylides. This catalyst shows a remarkable reactivity at low catalyst loading (0.5-3 mol %), affording in good yields the endo adducts with exceptional levels of enantioselectivity (up to >99% ee). This catalytic asymmetric procedure has a broad structural scope with regard to both azomethine and dipolarophile substitution. The first examples of catalytic asymmetric 1,3-dipolar cycloaddition with ketimine-derived azomethines are reported.