Catalytic oxidation of imines based on methyltrioxorhenium/urea hydrogen peroxide: a mild and easy chemo- and regioselective entry to nitrones.

[reaction: see text] The first successful catalytic oxidation procedure for the chemoselective conversion of imines to nitrones is reported. The reaction is general, high yielding, and user and environmentally friendly, and furnishes a solution to the yet unanswered issue of regioselective access to nitrones by oxidation of nitrogen derivatives.