Highly Efficient CH Hydroxylation of Carbonyl Compounds with Oxygen under Mild Conditions

A transition-metal-free Cs2 CO3 -catalyzed α-hydroxylation of carbonyl compounds with O2 as the oxygen source is described. This reaction provides an efficient approach to tertiary α-hydroxycarbonyl compounds, which are highly valued chemicals and widely used in the chemical and pharmaceutical industry. The simple conditions and the use of molecular oxygen as both the oxidant and the oxygen source make this protocol very environmentally friendly and practical. This transformation is highly efficient and highly selective for tertiary C(sp(3) )H bond cleavage.