The room temperature hydrogenolysis by LiAlH4-AlCl3 of ether solutions of a number of 1, 3- dioxolanes has been studied. Electron donor substituents on the C2 atom of the ring accelerate while electron acceptor substituents on C2 retard the reductive ring cleavage. The same effect but to a lesser extent is observed when these substituents are attached to the C4 or C5 atom of the ring. When electron donor substituents are attached to C4, ring ...