910617-53-7Relevant articles and documents
β-Enolization in α-phenyl-α,α',α'-trimethylcycloalkanones
Sifton, Wendy,Stothers, J. B.,Thomas, Shirley E.
, p. 1274 - 1280 (2007/10/02)
Ring expansion through β-proton abstraction from α-methyl groups has been observed for the α-phenyl-α,α',α'-trimethyl derivatives of cyclopentanone and cyclohexanone upon treatment with t-BuO(1-)/t-BuOH/185 deg C.This contrasts with the lack of rearrangement found for the α,α,α',α'-tetramethyl derivatives but is analogous to the behavior of some α-phenyl acyclic ketones.However, this process is reversible in the cyclic systems, but irreversible in the acyclic cases.For all of these α-phenyl substituted ketones, rearrangement is in competition with Haller-Bauer type cleavage.In the cyclic systems, a minor process was ob served whereby some of the ring-expanded product is reduced to the corresponding secondary alcohol but there was no evidence of rearrangement through γ-enolate formation involving phenyl proton abstraction, which is a minor process in the α-phenyl acyclic systems.
