Convergent, stereoselective syntheses of the glycosidase inhibitors broussonetines C, O and P

The first syntheses of the polyhydroxylated alkaloids (iminosugars) broussonetines O and P, glycosidase inhibitors of the pyrrolidine class, have been performed in a convergent, stereocontrolled way from d-serine as the chiral starting material. The synthesis of broussonetin C, a further member of this compound family, is also reported. A cross-metathesis step was one key feature of the synthesis. The versatility of the synthetic concept chosen permits the access to many members of this compound family, both natural ones and analogues thereof.