A short stereoselective synthesis of the protected uracil 3′-epi-polyoxin C

A short synthetic approach to the protected uracil 3′-epi-polyoxin C 20 has been developed. The stereoselective 3,3]-sigmatropic rearrangement of the corresponding 7-thiocyanato-α-d-xylo-hept-5-enfuranose 6 was employed as the key step to construct the C-5 stereocentre in 5-isothiocyanato-α-d-gluco-hept-6-enfuranose 8 and the formal synthesis of uracil 3′-epi-polyoxin C has been accomplished for the first time. This synthesis provides a facile method for multigram scale preparation and thus is useful for the research into the polyoxins’ structure-activity relationship and to search for more potent and effective anticandidal agents.