Synthesis of casuarines [pentahydroxylated pyrrolizidines] by sodium hydrogen telluride-induced cyclisations of azidodimesylates
摘要:
The key step in the synthesis of four diastereomers of casuarine from eight carbon sugar lactones is the efficient reduction of open chain azidodimesylates by sodium hydrogen telluride [Suzuki-Takaoka reduction] to allow the formation of the pyrrolizidine nucleus by bicyclisation. This is the first report of the synthesis of such highly oxygenated pyrrolizidines. (C) 1997 Elsevier Science Ltd.