Total synthesis of neokotalanol,a potent α-glucosidase inhibitor isolated from Salacia reticulata

Neokotalanol,a potent -glucosidase inhibitor isolated from Salacia reticulata,was synthesized through a key coupling reaction between a perbenzylated thiosugar and an appropriately protected perseitol triflate derived from D-mannose.This key step was found to be quite temperature dependent,and a simultaneous cyclization of the triflate leading to a characteristic 2,4,7-trioxabicyclo4.2.1nonane system was detected.