Electronic control of enantioselectivity in the palladium-catalyzed asymmetric allylic substitution of trans 4- tbutyl-l-vinylcyclohexyl benzoates

Abstract

The enantioselectivity in the palladium-catalyzed substitution of allylic benzoates 1 by sodium dimethyinwlonate was influenced by polar and steric effects of the substituents in the phenyl ring of the benzoate. Electron-donating p-substituents afforded effective chiral differentiation (up to 90%ee). Electron-withdrawing substituents, t-butyl-p-substituent, N,N-dialkylamino p-substituents were or o-substituents were detrimental to steric differentiation (down to 22%ee). Di- and tri-methoxy substituted benzoates gave moderate asymmetric inductions (46–70 %ee).