Synthesis of Spirocyclic Glucose-Proline Hybrids (GlcProHs)
作者:Frank Schweizer、Kaidong Zhang
DOI:10.1055/s-2005-922768
日期:——
A short synthetic route to polyhydroxylated spirocyclic glucose-based l-proline analogues is described from easily prepared 2,3,4,6 tetra-O-benzyl-d-glucono-lactone. The synthesis involves C-glycosylation of an exocyclic glucose-based epoxide with allyltributylstannane that affords functionalized C-ketosides containing an α-hydroxy ester moiety. Oxidation of the alcohol function, followed by stereoselective reductive amination provides an amine that undergoes iodine-induced aminocyclization to provide spirocyclic glucose-proline hybrids bearing an iodomethylene side-chain. The iodo function of the side-chain can be converted into other functional groups such as ester and hydroxyl groups, thereby allowing additional modifications to the pyrrolidine ring.