Diastereoselective free-radical reactions. Part 2. Synthesis of 2-deoxy-β-C-pyranosides by diastereoselective hydrogen-atom transfer
Abstract
C-Glycosides of 2,3-dideoxy-arabino-heptulosonate esters are prepared from the corresponding 2,3dideoxy-1-phenylsulphonyl derivatives by reductive desulphonylation with lithium naphthalenide and quenching of the so-formed enolate with appropriate alkyl halides. These C-glycosides are saponified and decarboxylated by the Barton O-acyl thiohydroxamate protocol to give 2-deoxy-β-C-glycosides with very high diastereoselectivities.