Synthetic studies towards the total synthesis of the saframycins
Ajeck-Carman, Karen Lynn
Doctor of Philosophy
A key improvement to the original saframycin B synthesis involves efficient sequential piperazinedione condensations to yield a basic saframycin skeleton from which all congeners might be made. Approaches toward the total synthesis of saframycin A result in formation of two advanced intermediates. The first, a pentacyclic diphenol nitrile with at least four out of five stereocenters established, is synthesized via a multistep scheme which involves a Pictet-Spengler type phenolic cyclization. The second advanced intermediate is produced via a route which involves cleavage of an imidazolidine ring with concomitant introduction of cyanide. An isomer of saframycin A is synthesized using this approach.