One-pot synthesis of C-glycosylic compounds (C-glycosides) from d-glucal, p-tolylsulfenyl chloride and aromatic/heteroaromatic compounds in the presence of Lewis acids Original Research Article

In the presence of Zn(CN)2, benzylated 2-thio-2-S-(p-tolyl)pyranosyl chlorides (2) generated in situ from tri-O-benzyl-d-glucal and p-TolSCl, smoothly react with thiophene, 2-methylthiophene, furan, 2-methylfuran, and N-methylpyrrole to give heteroaryl 2-thio-2-S-(p-tolyl)-C-β-d-glucopyranosylic compounds (C-glycosides) in good yields. Upon treatment with SnCl4, the reaction of chlorides 2 with thiophene or 1,4-dimethoxybenzene provides the corresponding benzylated C-β-d-glucofuranosylic derivatives. Under the same conditions, the use of 2-methylthiophene, furan, 2-methylfuran, or N-methylpyrrole yields (2S,3R,4R,5S)-1,3,4-tribenzyloxy-6,6-diheteroaryl-5-(p-tolylthio)-2-hexanoles. Treatment of 2 and mesitylene with AgBF4 yielded 1,6-anhydro-3,4-di-O-benzyl-2-thio-2-S-(p-tolyl)-β-d-glucose.