Importance of steric hindrance in linear coordination of Lewis acids with α-enones

Abstract

The complexation of α-enones [(E)-MeC(H)C(H)COR] with SnCl₄ and TiCl₄ has been studied with NMR spectroscopy as well as semiempirical and ab initio SCF-MO methods, which indicate a preference for linear coordination of Lewis acids with α-enones due to the steric effect of R group (R = Bu^t, Ph, 2,4,6-Me₃C₆H₂, 4-MeOC₆H₄) in the s-cis conformation.