Preparation of β′-phenylsulfonyl α,β-unsaturated ketones and unsymmetric dialkenyl ketones from 2-alkenyl-2-methoxycyclopropyl phenyl sulfones

β′-Phenylsulfonyl α,β-unsaturated ketones, which can be easily converted to unsymmetric dialkenyl ketones, were prepared via ring opening reactions of 2-alkenyl-2-methoxycyclopropyl phenyl sulfones.