Dichloroketene-olefin cycloadducts, α, α-dichlorocyclobutanones, are easily converted to α- chloroenones through a 3-step (2-pot) sequence of reactions. The over all result is the insertion of a functionalized 2-carbon unit between the original olefinic carbons. The efficiency of the method is demonstrated by a high-yield synthesis of d, 1-muscone.