Structurally well-defined, recoverable C3-symmetric tris(beta-hydroxy phosphoramide)-catalyzed enantioselective borane reduction of ketones.
[reaction: see text] A series of new chiral C(3)-symmetric tris(beta-hydroxy phosphoramide) ligands have been synthesized via the reaction of trisphosphoramide ester and Grignard reagents. The catalytic asymmetric borane reduction of ketones with these new C(3)-symmetric chiral tris(beta-hydroxy phosphoramide)s was investigated. Structurally well-defined, recoverable ligand 1d is an efficient catalyst for the enantioselective borane reduction of both electron-deficient and electron-rich ketones, and high enantioselectivities were achieved (up to 98% ee).
Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China. dudm@pku.edu.cn
Da-Ming
DM
Du
Tao
T
Fang
Jiaxi
J
Xu
Shi-Wei
SW
Zhang