The Ruthenium/TEMPO- Cataly sed Aerobic Oxidation of Alcohols

an efJicient catalytic system for the aerobic oxidation of a variety of primary and secondary alcohols, giving the corresponding aldehydes and ketones, in> 99 per cent selectivity in all cases. This interesting catalytic system is probably based on a hydridometal mechanism, involving a ‘RuH2(PPh~).~’-species as the active catalyst. TEMPO acts as a hydrogen transfer mediator and is regenerated by oxygen. The catalytic conversion of primary alcohols into aldehydes and of secondary alcohols into ketones is essential for the preparation of many key synthetic intermediates in organic chemistry (1). Traditional methods for performing such transformations generally involve the use of stoi-chiometric quantities of inorganic oxidants, notably chromium(VI) reagents (2), and generate copious quantities of inorganic waste. Hence, the quest for effective catalytic systems that use dea