title: Synthesis of C3-symmetric tris(beta-hydroxy amide) ligands and their Ti(IV) complex-catalyzed enantioselective alkynylation of aldehydes.
abstract: [reaction: see text]. A series of new chiral C3-symmetric tris(beta-hydroxy amide) ligands have been synthesized via the reaction of 1,3,5-benzenetricarboxylic chloride and optically pure amino alcohols (up to 96% yield). The asymmetric catalytic alkynylation of aldehydes with these new C3-symmetric chiral tris(beta-hydroxy amide) ligands and Ti (O(i)'Pr)4 was investigated. Ligand 4c synthesized from (1R,2S)-(-)-2-amino-1,2-diphenylethanol is effective for the enantioselective alkynylation of various aldehydes, and high enantioselectivity was obtained with aromatic aldehydes and alpha,beta-unsaturated aldehyde (up to 92% ee).
authors.affiliation: Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, PR China.
authors.forename: Tao
authors.initials: T
authors.lastname: Fang
authors.forename: Da-Ming
authors.initials: DM
authors.lastname: Du
authors.forename: Shao-Feng
authors.initials: SF
authors.lastname: Lu
authors.forename: Jiaxi
authors.initials: J
authors.lastname: Xu