The oxidation of copper(I) phenanthroline by /center dot/CH/sub 2/CH/sub 2/OH and /center dot/CH/sub 2/C(CH/sub 3/)/sub 2/OH free radicals yields ethylene and 2-methylpropene, respectively. During this process transients with a copper-carbon /sigma/-bond have been observed with an absorbance similar to that of copper(I) phenanthroline in the visible region. Rate constants for the formation of these transients are estimated to be larger than 10/sup 10/ M/sup /minus/1/ s/sup /minus/1/. These intermediates decompose via a /beta/-hydroxyl elimination reaction with specific rate constants of (1.7 /plus minus/ 0.4) /times/ 10/sup 3/ and (1.1 /plus minus/0.3) /times/ 10/sup 4/ s/sup /minus/1/ for /center dot/CH/sub 2/C(CH/sub 3/)/sub 2/OH and /center dot/CH/sub 2/CH/sub 2/OH in the pH range 4-10, respectively. The mechanism of the decomposition is discussed, and a stability constant for the ligation of /center dot/CH/sub 2/C(CH/sub 3/)/sub 2/OH and /center dot/CH/sub 2/CH/sub 2/OH to the cuprous complex is estimated to be larger than 6 /times/ 10/sup 6/ M/sup /minus//. 28 refs., 5 figs., 3 tabs.