HYDROGENOLYSIS BY AlCl3–LiAlH4 OF ETHER SOLUTIONS OF cis AND trans ISOMERS OF 2,4-DISUBSTITUTED-1,3-DIOXOLANES

Abstract

Hydrogenolysis by LiAlH4–AlCl3 of ether solutions of the cis and trans isomers of both 2,4-dimethyl-1,3-dioxolane and 2-ethyl-4-methyl-1,3-dioxolane have been carried out.The cis isomers are hydrogenolyzed respectively about 6.8 times and 10 times faster than are the corresponding trans isomers. The ratio of C2—O1 to C2—O3 bond cleavage in the cis isomers is at least 15 to 1 while that for the trans isomers is about 1 to 2. Isomerization during the aluminium chloride catalyzed hydrogenolysis is not detectable for the trans isomers. Slight indications of isomerization are discerned for the cis isomers.