Highly stereoselective allylation of a series of chiral tricarbonylchromium benzaldimine complexes (2a-c) was achieved at -20 degrees C and homoallyl amine complexes (4a-c) were isolated in good yields. In the case of homoallyl amine 4c, 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 4c was determined by X-ray diffraction, which showed a (S,S) or (R,R) configuration, in agreement with the stereochemical model operating for the ortho-substituted tricarbonylchromium arene complexes. Furthermore, the new tricarbonylchromium complex of N-(2-methoxybenzyliden)diphenyl phosphinamide 3 was prepared. This substrate is a stable analog of the normally unviable ammonia imine. (C) 2000 Elsevier Science S.A. All rights reserved
Maiorana, S., Baldoli, C., Del Buttero, P., Licandro, E., Papagni, A., Lanfranchi, M., et al. (2000). Studies of the stereoselective allylation of chiral benzaldimine chromium tricarbonyl complexes. JOURNAL OF ORGANOMETALLIC CHEMISTRY, 593, 380-387 [10.1016/S0022-328X(99)00601-4].
Studies of the stereoselective allylation of chiral benzaldimine chromium tricarbonyl complexes
PAPAGNI, ANTONIO;
2000
Abstract
Highly stereoselective allylation of a series of chiral tricarbonylchromium benzaldimine complexes (2a-c) was achieved at -20 degrees C and homoallyl amine complexes (4a-c) were isolated in good yields. In the case of homoallyl amine 4c, 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 4c was determined by X-ray diffraction, which showed a (S,S) or (R,R) configuration, in agreement with the stereochemical model operating for the ortho-substituted tricarbonylchromium arene complexes. Furthermore, the new tricarbonylchromium complex of N-(2-methoxybenzyliden)diphenyl phosphinamide 3 was prepared. This substrate is a stable analog of the normally unviable ammonia imine. (C) 2000 Elsevier Science S.A. All rights reserved
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