Heteroatom substituents on the methyl group of 2-methyl-1, 3-dioxolane retard the rate of hydrogenolysis by AlH2Cl of ether solutions of the 2-substituted 1, 3-dioxolanes. The effectiveness of the heteroatoms in decreasing the ease of hydrogenolysis is H< S< O< Br< NR2. This retardation is thought to be due to the destabilization of the transition state leading to the intermediate oxocarbonium ion, caused by the electronegativity of the heteroatom ...