A FACILE ROUTE TO MACROCYCLIC KETONES. DIRECT DIVINYLATION OF 2-CHLOROCYCLODODECAN-1-ONE

Abstract
The reaction of 2-chlorocyclododecan-1-one with vinylmagnesium chloride (molar ratio at 1:2) gave directly 1,2-divinylcyclododecan-1-ol, which was easily converted to 5-cyclohexadecen-1-one. This one-step divinylation was found to proceed not through a direct displacement of the Grignard reagent with the chlorine atom, but through a pinacol-like rearrangement of a vinyl group.