Novel imidazole-containing boronic acid and palladium hybrid catalysis for regioselective O-allylation of carbohydrates has been developed. This catalytic process enables the introduction of a useful allyl functional group into the equatorial hydroxy group of cis-1,2-diols of various carbohydrates with low catalyst loading and excellent regioselectivities. This is the first report on hybrid catalysis
Synthesis of β-(1→2)-Linked 6-Deoxy-<scp>l</scp>-altropyranose Oligosaccharides via Gold(I)-Catalyzed Glycosylation of an <i>ortho</i>-Hexynylbenzoate Donor
The β-(1→2)-linked 6-deoxy-l-altropyranose di- to pentasaccharides 2–5, relevant to the O-antigen of the infectious Yersinia enterocolitica O:3, were synthesized for the first time. The challenging 1,2-cis-altropyranosyl linkage was assembled effectively via glycosylation with 2-O-benzyl-3,4-di-O-benzoyl-6-deoxy-l-altropyranosyl ortho-hexynylbenzoate (7) under the catalysis of PPh3AuNTf2. NMR and molecular