Small-Ring Compounds. XXXVI. 3-Methylenecyclobutyl Bromide and 1-Methylcyclobut-2-enyl Bromide

3-Methylenecyclobutyl bromide and 1-methylcyclobut-2-enyl bromide have been synthesized from the cycloaddition products of allene with acrylonitrile and vinyl benzoate. The rate constants for solvolysis of the two bromides in aqueous ethanol have been determined and correlated with the solvolysis rates of a series of analogous bromides. 1-Methylcyclobut-2-enyl bromide appears to exhibit some rate enhancement due to cross-ring s-type interaction of the electrons formally centered on the 3-position with the electron-deficient 1-position in the transition state