Ene reactions of acyl nitroso intermediates with alkenes and their halocyclization

Highly reactive acyl nitroso intermediates were formed in situ by transition metals-catalyzed hydrogen peroxide oxidation of hydroxamic acids 1a-b and these transient species trapped with alkenes 2a-c to afford the corresponding ene products 3a-d and 4b up to 91% yield, and halocyclization of 3d gave substituted oxazolidinone 5a in 77% yield. (C) 2004 Elsevier Ltd. All rights reserved.