2. 2. 0.

Article abstract of DOI:10.1021/ja00518a040

Two new syntheses of cyclobutene esters and the use of 1-cyanocyclobutene as potential isoprene synthons are described. Photocycloaddition of methyl cyclobut-1-enecarboxylate and 1-cyanocyclobutene to piperitone, followed by reduction and lactonization, gives photodihydroarisolactone. Single-crystal X-ray analysis of the latter and a related compound reveals interesting structural features in the strained bicyclo left bracket 2. 2. 0 right bracket hexane system. Thermolysis of these lactones yields 1,5-cyclodecadienes related to germacrene sesquiterpenes.