Role of 2-oxonia cope rearrangements in prins cyclization reactions

[GRAPHICS] The 2-oxonia Cope rearrangement is undetectable in typical Prins cyclizatio n reactions. We have investigated the Cope rearrangement in a Prins cycliza tion reaction using a competitive reduction of the oxocarbenium ion interme diate, and a racemization reaction mediated by the rearrangement. In our un activated substrate, the 2-oxonia Cope rearrangement was much faster than P rins cyclization. An enantioselective allyl transfer reaction also was deve loped using a 2-oxonia Cope rearrangement.