New rearrangement of 4-isoxazoline system: conversion of ketones into a,b-unsaturated amides

A new rearrangement pattern of the 4-isoxazoline system is reported. The reaction, starting from 3,3-disubstituted derivatives and leading to α,β-unsaturated amides, proceeds through the quaternarization of the nitrogen atom and involves the heterolytic cleavage of C3-N bond, assisted by the formation of a relatively stable intermediate. The overall process represents a useful conversion of ketones into α,β-unsaturated amides.