A Very Efficient Synthesis of a Mannosyl Orthoester [2]Rotaxane and Mannosidic [2]Rotaxanes

The direct preparation of mannosyl[2]rotaxane derivatives by O-glycosylation from tetra-O-acetyl-alpha-D-mannosyltrichloroacetimidate and a tert-butylanilinium alcohol in the presence of dibenzo-24-crown-8 is described. The method appears to be very efficient and allows for the preparation of either orthoester or mannosyl rotaxane derivatives, depending on reaction conditions.