
%0 Journal Article
%A Brown, RFC 
%A Eastwood, FW 
%A Jackman, GP 
%T Methyleneketenes and methylenecarbenes. IX. Thermal rearrangements of Alkyl-and Aryl-acetylenes involving Alkyl- and Aryl-methylenecarbenes
%J Australian Journal of Chemistry
%D 1977/08/01
%V 30
%N 8
%P 1757-1767
%K 
%R https://doi.org/10.1071/CH9771757
%U https://www.publish.csiro.au/paper/CH9771757 
%X Flash vacuum pyrolysis of 1-(1?-adamantyl)acetylene[2-14C] (780°) gives recovered alkyne which contains 25% of the rearranged product, 1-(1?- adamantyl)acetylene[1-14C]. 1-Ethynyl-1-methylcyclohexane(740°) is converted into toluene and benzene, while evidence for rearrangement of 3,3-dimethylbut-1-yne[2-13C] (790°) and 3-methyl-3-phenylbut-1-yne[2- 13C] (680°) was not obtained before the onset of alternative reactions. These reactions of alkyl-substituted alkynes are discussed in terms of possible methylene carbene intermediates. Similar intermediates may possibly be involved in reactions of arylalkynes. Thus, pyrolysis of 1- ethynylnaphthalene (750°) yields acenaphthylene and of 1-ethynyl-8- methylnaphthalene (750°) yields phenalene. The pathways for the formation of 2-phenyl- and 3-phenyl-indene from (2- methylphenyl)phenylethyne (790°) and of indene from (2- methylphenyl)ethyne (740°) are obscured by facile thermal rearrangements. 
