Thermolysis of 2-Benzylidenebenzocyclobutenols

Article abstract of DOI:10.1021/jo00050a038

The thermolysis of a series of 2-benzylidenebenzocyclobuten-1-ols has been studied.Whenever comparisons can be made, the rate of opening of the benzocyclobutene ring was slower for these compounds than the corresponding 2-ones.The intermediate vinylallenes underwent a variety of electrocyclization reactions which depended on the nature of the additional substituent at C-1. 10-Benzylideneanthrone and 4-benzylidene-1-tetralones, respectively, were obtained when this substituent was phenyl or vinyl. 1-(Alkynylphenyl)-2-benzylidenebenzocylobuten-1-ols were converted to mixtures of 4-benzylidene-1,4-naphthoquinonemethides, 2,3-dibenzylidene-1-indanones, and 10-phenylbenzofluorenone.