Studies of the stereoselective allylation of chiral benzaldimine chromium tricarbonyl complexes

Highly stereoselective allylation of a series of chiral tricarbonylchromium benzaldimine complexes was achieved at -20° and homoallyl amine complexes, e.g. I, were isolated in good yields. In the case of homoallyl amine I, obtained in 75% d.e., the degree of stereoselection depends on the catalyst and the reaction conditions. The crystal structure of the major diastereoisomer of racemic I was detd. by x-ray diffraction, which showed a (S,S) or (R,R) configuration, in agreement with the stereochem. model operating for the ortho-substituted tricarbonylchromium arene complexes. Furthermore, the new tricarbonylchromium complex of N-(2-methoxybenzylidene)diphenyl phosphinamide was prepd. This substrate is a stable analog of the normally un-viable ammonia imine