Titanium tridentate Schiff

The same conversion is successfully catalyzed by using in-situ generated complexes of Ti(OPr )4 and tridentate Schiff bases (Stmcture 54), which are derived from substituted salicylaldehydes with chiral aminoalcohols [85]. Another similar chiral reagent is derived from reaction of titanium tetraisopropoxide and the Schiff base of 3,5-di-tert-butylsalicylaldehyde and (5)-valinol. The mechanism and stereoselectivity of these chiral Lewis acids are discussed by Corey and co-workers. Other chiral Ti Schiff base complexes have been employed in asymmetric TMSCN addition to benzaldehyde [85]. 

The carbon allylation of tertiary alcohols and derivatives provides a simple access to the formation of quaternary carbon centers. The chiral titanium complex prepared from tridentate Schiff base and Tip4 has been reported to catalyze a... 

Tridentate chiral Schiff bases derived from (- -)-Q -pinene (123) catalyse enantioselective addition of diethylzinc to aryl aldehydes. Steric, aryl stacking, and electronic effects are significant in the transition state, the latter being probed by a Hammett plot of ee versus for a series of benzaldehydes. Complexes of the Schiff base (123) with titanium(IV) catalyse enantioselective cyanation. ... 

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