Photoinitiated hydrothiolation of pyranoid exo-glycals: the d-galacto and d-xylo cases

Radical-mediated addition reactions of thiols to O-peracetylated exo-galactal and exo-xylal with 2,2-dimethoxy-2-phenylacetophenone as the photoinitiator resulted in high yielding formation of the corresponding β-d-glycopyranosylmethyl-sulfide derivatives (2,6-anhydro-1-deoxy-1-S-substituted-1-thio-alditols) with exclusive regio- and very high stereoselectivity, including disaccharide mimicks with Gly-CH2-S-Gly scaffolds. [Display omitted] •Photoinitiated thiol-ene reaction of O-peracetylated exo-glycals.•Synthesis of β-d-glycopyranosylmethyl-sulfide type glycomimetics.•Exclusive regio- and stereoselectivity with exo-galactal.•Exclusive regio- and very high stereoselectivity with exo-xylal.•Disaccharide mimicks of Gly-CH2-S-Gly scaffolds.