IODIDE SALTS OF CERTAIN RHODIUM COMPLEXES OF ASYMMETRIC DIPHOSPHINES, THEIR PREPARATION AND THEIR USE IN ENHANCEMENT OF ENANTIOSELECTIVITY IN THE PRODUCTS OF THEIR REDUCTION OF PROCHIRAL IMIDAZOLINONES

摘要

A method for the attainment of enhanced enantioselectivity in the reduction of 3-acyl derivatives of 1-(2-alkoxyethyl)-4-phenyl-imidazolin-2-ones to the optically active 3-acyl derivatives of 1-(2-alkoxyethyl)-4-phenyl-2-imidazolidones for use in the direct manufacture of levamisole, (-), 2, 3, 5, 6-tetrahydro-6-phenylimidazo-¢2,1-b!-thiazole, useful as an anthelmintic has been discovered. The method involves the preferred use of iodide salts of Rh(I) complexes of optically active bistertiary phosphines of the formula: to achieve maximum enantioselectivity. The methods for preparing the iodide salts are disclosed.