Though cyclizations following the general template above had been observed prior to Nazarov 's involvement , it was his study of the rearrangements of allyl vinyl ketones that marked the first major examination of this process . Nazarov correctly reasoned that the allylic olefin isomerized in situ to form a divinyl ketone before ring closure to the cyclopentenone product . The reaction shown below involves an alkyne oxymercuration reaction to generate the requisite ketone .