The cleavage of tetramethyl-l, 3-cyclobutane-dione (dimethylketene dimer, I) by alcohols is catalyzed by basic reagents and leads to esters of 2, 2, 4-trimethyl-3-oxovaleric acid. 2 The 0- lactone dimer of dimethylketene (11) is a more reactive acylating reagent than dimer I, but it also reacts sluggishly with alcohols unless a catalyst, preferably a base, is present. In the absence of active hydrogen compounds, the lactone dimer 11, heated at moderate ...
