CH3 (CH3) d2= CH2+ H2C= 0+ Bre Thus, this cleavage reaction is an extended chain analog of the usual elimination reaction which generally accompanies substitution, but which is impossible here because of the lack of P-hydrogen atoms. A few other examples of this type of elimination have been reported, as in the cases of 0-dimethylpivalophenone methiodidea and a-tosyloxy-8,~-dimethyl-~-butyrolactone, g and the reverse aldol reaction ...