Asymmetric direct α-hydroxylation of β-oxo esters catalyzed by chiral quaternary ammonium salts derived from cinchona alkaloids.
Cinchona alkaloid-derived chiral quaternary ammonium organocatalysts were developed. The catalyst with a bulky 1-adamantoyl group at the C-9 position promoted the enantioselective α-hydroxylation of β-oxo esters and resulted in the corresponding products in 35-95% yields and 58-90% ee. The reaction was successfully scaled to a gram-quantity scale with a similar yield without loss of enantioselectivity.
State Key Laboratory of Fine Chemicals, School of Pharmaceutical Science and Technology, Dalian University of Technology, Dalian 116024, China.
Hongjie
H
Yao
Mingming
M
Lian
Zhi
Z
Li
Yakun
Y
Wang
Qingwei
Q
Meng
D002384:Catalysis; D002930:Cinchona Alkaloids / Q000737:chemistry*; D004952:Esters; D006900:Hydroxylation; D015394:Molecular Structure; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D012492:Salts / Q000737:chemistry*; D013237:Stereoisomerism
D002930:Cinchona Alkaloids; D004952:Esters; D000644:Quaternary Ammonium Compounds; D012492:Salts