| The application of ring-expansion reactions of donor-acceptor cyclopropanes toward natural product synthesis is described. The first total synthesis of phyllantidine, a member of the Securinega alkaloids, has been accomplished. The preparation of the tetrahydro-1,2-oxazine core of the natural product was achieved using the reaction of nitrones and cyclopropanes; the first application of the reaction in total synthesis. The development of the reaction of imines with cyclopropanes and its use toward the synthesis FR901483 of is also discussed. FR901483 is a potent immunosuppressive agent that has received considerable attention from the synthetic community. The successful route toward FR901483 required the development of an intramolecular variation of the reaction of imines and cyclopropanes, and is another example of the use of cyclopropanes for the construction of complex heterocycles in organic synthesis. |
