Rearrangement Reactions of 1,1-Divinyl-2-phenylcyclopropanes

Abstract

1,1-Divinyl-2-phenylcyclopropanes are entry points to a rich area of rearrangement chemistry. With N,N-diallyl amide substrates, tandem radical cyclizations can be initiated at room temperature. Warming provides products of pure thermal rearrangements with acids, ester, and amides. These isomerizations give vinylcyclopentenes resulting from divinylcyclopropane rearrangements and more deeply rearranged tricyclic spirolactams resulting from aromatic Cope rearrangements followed by ene reactions. Conversion of the carbonyl group to an alcohol or ether opens retro-ene pathways followed by either tautomerization or Claisen rearrangement.