On the formation of ethoxy alcohols from reaction of trans-1,2-Epoxy-3-methyl-1,3-diphenylbutane and 1,2-Epoxyoctane with boron trifluoride etherate

Abstract

Reaction of trans-1,2-epoxy-3-methyl-1,3-diphenylbutane (1) with boron trifluoride etherate in benzene gave 3-methyl-2,3-diphenylbutanal (3), shown by deuterium labelling experiments to be formed by C1-O cleavage and alkyl migration, and (1RS,2RS)-l-ethoxy-3-methyl-1,3-diphenyl- butan-2-ol (16) in a process involving retention of configuration at Cl. In ether as solvent the epoxide gave, in addition to aldehyde (3) and ethoxy alcohol (16), 3-methyl-1,3-diphenylbutan-2-one (11) and vinyl ethers (19) and (20). Reaction of 1,2-epoxyoctane (17a) with boron trifluoride etherate in ether gave 1-ethoxyoctan-2-ol (18a) shown by deuterium labelling experiments to be formed by inversion of configuration at C1. The mechanistic implications of these results are discussed.