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