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
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
Methylhydrazine-induced enantioselective α-hydroxylation of β-keto esters with molecular oxygen catalyzed by hydroquinine
作者:Yakun Wang、Ting Xiong、Qingwei Meng
DOI:10.1016/j.tet.2014.11.029
日期:2015.1
Methylhydrazine-induced α-hydroxylation of β-dicarbonylcompounds was achieved using O2 as the oxygen source. This reaction provides an efficient approach to enantioenriched ɑ-hydroxy β-dicarbonylcompounds, which are valuable substances and widely used in the chemical and pharmaceutical industry. A wide variety of β-keto esters could undergo this oxidation to give the corresponding products in excellent