Pyrolysis of three acetates of methylbicyclo[2.2.1]heptan-2-ols and the parent alcohols

Abstract

The acetates of exo-2-methyl-endo-bicyclo[2.2.1]heptan-2-ol, endo-2-methyl-exo-bicyclo-[2.2.1]heptan-2-ol, and 1-methyl-exo-bicyclo[2.2.1]heptan-2-ol together the parent alcohols have been pyrolysed at several temperatures and the product distribution determined. The mechanism and direction of elimination in relation to structure are discussed qualitatively. The formation of the principal products is consistent with a concerted elimination involving a six-membered cyclic transition state. Wagner–Meerwein rearrangement occurs as a competing reaction in cases where the formation of a tertiary structure is possible at the expense of a secondary one. In the case studied a two-step reaction is considerably faster than direct pyrolysis of the secondary structure.