Abstract
The thesis outlines the development of suitable methodology in order to prepare 2- imino-1,3,2-oxazaphosphorinanes. α-Methylbenzylamines were converted to the corresponding of 2-amino-2-oxo-1,3,2-oxazaphosphorinanes with good overall yields. Xray structures were obtained for both (2R)-chloro-3-[(R)-α-methylbenzyl]-2-oxo-1,3,2- oxazaphosphorinane and racemic 2-(R)-amino-3-[(R)-α-methylbenzyl]-2-oxo-1,3,2- oxazaphosphorinane. This conformational study clearly indicated that the exo cyclic P=O is equatorial whereas the chlorine and amino groups are axial. Aldimines were obtained upon heating the 2-amino-2-oxo-1,3,2- oxazaphosphorinanes under reflux in dichloromethane for 24 hours with two equivalents of 4-substituted benzaldehyde derivatives and five equivalents of titanium (IV) ethoxide. However, five equivalents of acetophenone and ten equivalents of titanium (IV) ethoxide and heating under reflux in toluene were necessary for the synthesis of the corresponding ketimine derivative. This novel class of activated imine underwent a diastereoselective 1,4-addition reaction with diethylaluminium cyanide (48% de). The major addition product was obtained in a diastereomerically pure form upon recrystallization from ethyl acetate and hexane.
