Enantioselective cyanosilylation of alpha,alpha-dialkoxy ketones catalyzed by proline-derived in-situ-prepared N-oxide as bifunctional organocatalyst.
Bifunctional N,N'-dioxide catalysts have been developed for highly enantioselective cyanosilylation of alpha,alpha-dialkoxy ketones. This process, catalyzed by in-situ-prepared proline-derived N,N'-dioxide 2b, produced the corresponding cyanohydrin trimethylsilyl ethers in excellent yields (up to 99%) with high enantioselectivities (up to 93% ee). A reasonable mechanism was proposed according to the observation of the linear effect, 1H NMR spectra, isolated cyanohydrin, and the roles of the NH and N-oxide moieties of the catalyst.
Qin
Bo
B
Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China.
Liu
Xiaohua
X
Shi
Jian
J
Zheng
Ke
K
Zhao
Haitao
H
Feng
Xiaoming
X
D000080:Acetals / Q000737:chemistry; D000438:Alcohols / Q000737:chemistry*; D002384:Catalysis; D003486:Cyanides / Q000737:chemistry*; D007659:Ketones / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D010087:Oxides / Q000737:chemistry*; D011392:Proline / Q000737:chemistry*; D013237:Stereoisomerism
D000080:Acetals; D000438:Alcohols; D003486:Cyanides; D007659:Ketones; D010087:Oxides; C059688:alkoxyl radical; D011392:Proline