Asymmetric 1,3-dipolar Cycloaddition Using Fesulphos

Aldrich ChemFiles 2008, 8.6, 14.

The asymmetric 1,3-dipolar cycloaddition reaction is of the utmost importance for the enantioselective synthesis of five-membered heterocycles. Cabrera et al. introduced a new family of ligands consisting of a planar chiral P,S-ligand, named Fesulphos, for the 1,3-dipolar cycloaddition of azomethine halides.¹ The catalytic reaction is carried out with the Fesulphos ligand, a copper salt, and triethylamine in methylene chloride. This new catalytic system demonstrated complete enantiocontrol (ee >99%) with conversion up to 97% (Scheme 1).

Scheme 1.

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References

1. Cabrera, S. et al. J. Am. Chem. Soc. 2005, 127, 16394.

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Materials