The first enantioselective direct α-hydroxylation of β-oxo esters was developed by using phase-transfercatalysis. 1-Indanone-derived 1-adamantyl (1-Ad) β-oxo esters, in the presence of commercially available cumyl hydroperoxide and a cinchonine-based ammonium salt, resulted in the corresponding products with 69–91 % yield and 65–74 % ee. The reaction had also been successfully scaled-up to a gram
highly enantioselective α-hydroxylation of β-ketoesters using cumene hydroperoxide (CHP) as the oxidant was realized by a chiral (1S,2S)-cyclohexanediamine backbone salen-zirconium(IV) complex as the catalyst. A variety of corresponding chiral α-hydroxy β-ketoesters were obtained in excellent yields (up to 99%) and enantioselectivities (up to 98% ee). The zirconium-catalyzed enantioselective α-hydroxylation
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
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