... Another interesting aspect of the chemistry of cyclo- butenes is thermal isomerixati~n,~~~~ which results in the formation of an open-chain diene. ... Can. J. Chem.. 34, 1413 (1956). (13) I. hl. Heilbron and HM Bunbury, "Dictionary of Organic Com- 81, 2723 (1959). Khim. ...