A total synthesis of the anti-tumor, ansa-macrocycle, Maytansine, is in progress. The four major fragments with most of the stereochemical features and functional groups are already in hand and only the convergence of these fragments into the final target remains to be done. Biochemical studies on the cyclic carbinol urethane are also being undertaken with regard to its alkylation of chemical and biological nucleophiles. A series of analogs containing the biologically active cyclic urethane are also being prepared to assess what structural features are critical for alkylation.