
%0 Journal Article
%A Brown, RFC 
%A Eastwood, FW 
%A Harrington, KJ 
%A McMullen, GL 
%T Methyleneketenes and methylenecarbenes. III. Pyrolytic synthesis of arylacetylenes and their thermal rearrangements involving arylrnethylenecarbenes
%J Australian Journal of Chemistry
%D 1974/11/01
%V 27
%N 11
%P 2391-2402
%K 
%R https://doi.org/10.1071/CH9742393
%U https://www.publish.csiro.au/paper/CH9742393 
%X Flash vacuum pyrolysis (550-600°) of 5-benzylidene derivatives of 2,2- dimethyl-1,3-dioxan-4,6-dione(isopropylidene malonate) gives phenylacetylenes bearing m- or p-substituents (H, Me, MeO, Cl, CN)in 64-98% yield. o-Methoxy- and o-phenyl-benzylidene derivatives give the arylacetylenes even at 420°. Arylacetylenes equilibrate with arylmethylenecarbenes, ArCH=C:, at 550-720°, as shown by labelling experiments using 13C and by the formation of products of interaction with o-substituents. Methylenebenzocyclobutene and o-tolylacetylene each form indene at 700-720°. 
