Enantioselective α-hydroxylation of β-keto esters catalyzed by chiral S-timolol derivatives
作者:Yuanchun Cai、Mingming Lian、Zhi Li、Qingwei Meng
DOI:10.1016/j.tet.2012.07.003
日期:2012.9
derived from the β-blocker inhibitor S-timolol determined the most active catalyst of asymmetric α-hydroxylation of β-ketoesters. (R)-1-(tert-butylamino)-3-(3,4,5-trimethoxyphenoxy) propan-2-ol (3k) was the most effective derivative, enantioselectively catalyzing α-hydroxylation of β-ketoesters using tert-butyl hydroperoxide as the oxidant in hexane to afford the corresponding products in excellent yield
A highly efficient α-hydroxylation of β-ketoesters catalyzed by cupreidine in the presence of cumyl hydroperoxide (CHP) was achieved. The reaction was applied to a wide variety of β-ketoesters to give products in high yields (up to 95%) with excellent enantioselectivities (up to 97% ee). The reaction had been successfully scaled up to a gram quantity and (S)-5-chloro-2-hydroxy-1-oxo-2,3-dihydro-
asymmetric α‐hydroxylation of β‐indanone esters and β‐indanone amides using peroxide as the oxidant was realized with a new C‐2′ substituted Cinchona alkaloid derivatives. The two enantiomers of α‐hydroxy‐β‐indanone esters could be obtained by simply changing the oxidant. This protocol allows a convenient access to the corresponding α‐hydroxy‐β‐indanone esters and α‐hydroxy‐β‐indanone amides with up to
Scheme 1. Diterpenoidalkaloidlappaconine and preparation of lappaconinederivatives.[a] State Key Laboratory of Fine ChemicalsSchool of Pharmaceutical Science and TechnologyDalian University of TechnologyNo. 2 Linggong Road, Ganjingzi District, Dalian, LiaoningProvince 116012, P. R. ChinaE-mail: mengqw@dlut.edu.cnhttp://ceb.dlut.edu.cn/index.html[b] Department of Pharmaceutics, Daqing CampusHarbin