87258-68-2Relevant academic research and scientific papers
Base Catalysed Rearrangements involving Ylide Intermediates. Part 18. Competing , , and Rearrangements of Ammonium Ylides
Chantrapromma, Kan,Ollis, W. David,Sutherland, Ian O.
, p. 1049 - 1062 (2007/10/02)
The rearrangements of acyl stabilised ammonium ylides are, in several cases, accompanied by competing rearrangements and in one case by a rearrangement.For examples involving migrating benzyl or phenylethyl groups the mechanism of these rearrangements has been studied.Thus the competing , , and rearrangements of the ylide (12) are largely intramolecular, but the intermolecularity is as high as 28percent for the and rearrangements and 14percent for the rearrangement in methanol at 55 deg C.The competing and rearrangements of the optically active (29a) give products with predominant retention of the configuration of the migrating phenylethyl group, but the intramolecular stereoselectivity of the rearrangement is significantly greater than that of the rearrangement.These results are consistent with a radical pair pathway for all three modes of rearrangement.Suitably substituted acyl stabilised allylammonium ylides (55) rearrange by competing , and processes.
