Catalytic asymmetric endo-selective [3+2] cycloaddition reactions of Schiff bases of α-aminophosphonates with olefins using chiral metal amides.

Catalytic asymmetric endo-selective [3+2] cycloaddition reactions of Schiff bases of α-aminophosphonates with olefins are described. While the efficient asymmetric synthesis of several phosphonate analogues of proline derivatives is important in bioorganic chemistry, a direct catalytic method to prepare optically active endo [3+2] cycloadducts of α-aminophosphonates with olefins has never been developed. We found for the first time that catalyst systems prepared from Group 11 metal amides with the (R)-FeSulphos ligand were effective for the asymmetric endo-selective [3+2] cycloaddition to afford the desired proline phosphonate analogues in high yields with high endo- and high enantioselectivities.