
%0 Journal Article
%A Crow, WD 
%A McNab, H 
%T Synthetic Applications of Intramolecular Insertion in Arylcarbenes. IV. o-Alkoxy-, Dialkylamino- and Alkylthio-1-phenylethylidenes
%J Australian Journal of Chemistry
%D 1979/01/01
%V 32
%N 1
%P 123-131
%K 
%R https://doi.org/10.1071/CH9790123
%U https://www.publish.csiro.au/paper/CH9790123 
%X A series of 1-phenylethylidenes, substituted in the ortho-position by alkoxy, dialkylamino and alkylthio side chains containing up to three carbon atoms, has been generated in the gas phase and pyrolysed at 250-750º/0.05-0.30 mm. Carbene insertion to form five-membered heterocyclic rings predominates, with up to 20% Bamford-Stevens insertion, to give the styrenes; little or no formation of six-membered rings is observed. In cases where stereoselective insertion is possible, the trans-disubstituted heterocycle is formed preferentially, the selectivity being greatest in the case of dialkylamino substitution. The mechanisms involved are discussed in terms of transition state geometry. 
