147600-17-7Relevant articles and documents
α-Pinene-type chiral Schiff bases as tridentate ligands in asymmetric addition reactions
Jaworska, Magdalena,Blocka, Ewelina,Kozakiewicz, Anna,Welniak, Miroslaw
experimental part, p. 648 - 657 (2011/07/08)
A group of tridentate Schiff bases derived from (+)-α-pinene were synthesized. The steric effects in the transition state, the importance of π-π stacking interactions as well as the electronic effects of aryl aldehydes according to Hammett constant values in the enantioselective addition of Et2Zn to aldehydes with the use of Schiff bases as chiral ligands are described. Also, a variety of aldehydes were cyanated using a catalyst prepared in situ from titanium tetraisopropoxide and chiral Schiff bases. The influence of a conjugated double-bond in the cyanation substrates on enantioselectivity was observed. The chemical structures of the chiral Schiff base-titanium alkoxide complexes are discussed based on their 1H and 13C NMR spectra. 3D models of the Zn2-complex catalyst and Ti-complex catalyst containing α-pinane-type Schiff bases based on X-ray diffraction experiments are postulated. The models presented were consistent with the reported chirality of the addition product and observed ee.
Salicylaldehyde Schiff bases derived from 2-ferrocenyl-2-amino alcohols. Part 1: New chiral ligands for the titanium-catalyzed enantioselective cyanation of aldehydes
Ma Moreno, Rosa,Rosol, Malgorzata,Moyano, Albert
, p. 1089 - 1103 (2007/10/03)
The condensation of a set of diversely substituted (S)-2-amino-2-ferrocenyl ethanol derivatives 1a-e with the salicylaldehydes 5A-C resulted in the generation of a small library of new chiral Schiff base-ligands, whose titanium isopropoxide complexes have
Asymmetric Carbon-Carbon Bond Forming Reactions Catalyzed by Chiral Schiff Base-Titanium Alkoxide Complexes
Hayashi, Masahiko,Inoue, Tetsuya,Miyamoto, Yasunori,Oguni, Nobuki
, p. 4385 - 4398 (2007/10/02)
The enantioselective addition of trimethylsilyl cyanide to a variety of aldehydes proceeded by the aid of a catalyst prepared in situ from titanium tetraisopropoxide and chiral Schiff bases and gave the corresponding cyanohydrins in high optical yield (up to 96percent e.e.).A remarkable rate enhancement was brought about by the addition of the Schiff base to the titanium alkoxide mediated silylcyanation of aldehydes.This catalyst system also promoted the highly enantioselective reaction of diketene with aldehydes, which led to the formation of optically active 5-hydroxy-3-oxoesters.