Exploiting the cross-metathesis reaction in the synthesis of pseudo-oligosaccharides

An approach to the synthesis of pseudo-oligosaccharides based on the cross-metathesis reaction between distinct sugar-olefins, followed by intramolecular cyclization of the obtained heterodimer, is presented. In particular, the relative efficiency of two alternative approaches, the straightforward cross-metathesis reaction and the two-step procedure (self-metathesis followed by cross-metathesis), was explored and compared for diverse sugar-olefin substrates. Some representative examples of intramolecular cyclization using iodine as an electrophilic promoter, are also reported.