Methylhydrazine-induced enantioselective α-hydroxylation of β-keto esters with molecular oxygen catalyzed by hydroquinine

Methylhydrazine-induced alpha-hydroxylation of beta-dicarbonyl compounds was achieved using O-2 as the oxygen source. This reaction provides an efficient approach to enantioenriched alpha-hydroxy beta-dicarbonyl compounds, which are valuable substances and widely used in the chemical and pharmaceutical industry. A wide variety of beta-keto esters could undergo this oxidation to give the corresponding products in excellent yields (up to 95%) and with good enantioselectivities (up to 85% ee). The mild reaction conditions and the use of molecular oxygen as oxidant make this protocol very environmentally friendly and practical. (C) 2014 Elsevier Ltd. All rights reserved.