Highly enantioselective copper(I)-fesulphos-catalyzed 1,3-dipolar cycloaddition of azomethine ylides.
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.
Cabrera
Silvia
S
Departamento de Química Orgánica, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain.
Gómez Arrayás
Ramón
R
Carretero
Juan C
JC