Rate constants for the individual competitive components of the oxy-Cope and acetylenic oxy-Cope reactions were detd. by pyrolyzing the component at 350 degrees with an internal std., 1-phenylbut-3-en-1-ol (1). The co- thermolysis of hexa-1,5-dien-3-ol and 1 afforded a 1.65 rate ratio with a 0.13 mean deviation. The addn.of a vinyl group to but-3-en-1-ol and but-3-yn-1-ol enhanced the beta-hydroxy olefin and beta-hydroxy acetylene cleavage rate by 12.5 and 11 times, resp. Chem Abstr. Vol. 75, 129204x.