A high temperature investigation using microwave synthesis for electronically and sterically disfavoured substrates of the Newman-Kwart rearrangement

Electronically deactivated and/or sterically hindered substrates undergo the Newman-Kwart rearrangement (NKR) at around 300 degrees C, beyond the range of most convenient and safe, small-scale laboratory equipment. We report here the convenient conversions of several difficult substrates using modern microwave technology, which has proven ideal for investigating this high temperature reaction in all but the most refractory of cases. In addition, several previously reported difficult examples were re-investigated, and found not to require high temperatures under these conditions, for various reasons which are elaborated upon. (C) 2007 Elsevier Ltd. All rights reserved.