
%0 Journal Article
%A Heard, GL 
%A Yates, BF 
%T Steric and Electronic Effects on the Mechanism of the Stevens Rearrangement&#8212;Large Organic Ylides of Unusually High Symmetry
%J Australian Journal of Chemistry
%D 1994/09/01
%V 47
%N 9
%P 1685-1694
%K 
%R https://doi.org/10.1071/CH9941685
%U https://www.publish.csiro.au/paper/CH9941685 
%X Ab initio molecular orbital theory has been used to study the Stevens rearrangement of trimethylammonium methylide, dimethylammonium formylmethylide and trimethylammonium formylmethylide . For each system, the rearrangement is predicted to proceed via dissociation to two radical species followed by recombination to the appropriate alkylamine . In no case is the concerted pathway competitive. Steric effects are less important than electronic effects in stabilizing the ylides, and the introduction of a carbonyl group lowers the energy barrier towards the ylides is predicted to have rigorous C8 symmetry; this unusual situation is brought about by the nature of the substituents around the positive nitrogen and the planarity of the remaining negative portion of the molecule. 
