Stereoselective synthesis of C-ketosides by sequential intramolecular hydrogen atom transfer–intermolecular allylation reaction

A tandem 1,5 or 1,6 hydrogen atom transfer (HAT)–radical allylation using carbohydrate models is described. The HAT reaction generated a C-glycos-1-yl radical intermediate, which added to allyltri-n-butyltin with high diastereoselectivity, to give C-ketosides with the quaternary carbon carrying two differently functionalized tethers.