Studies of the stereoselective allylation of chiral benzaldimine chromium tricarbonyl complexes
作者:Stefano Maiorana、Clara Baldoli、Paola Del Buttero、Emanuela Licandro、Antonio Papagni、Maurizio Lanfranchi、Antonio Tiripicchio
DOI:10.1016/s0022-328x(99)00601-4
日期:2000.1
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.