ChemInform Abstract: Synthetic Studies in the 5‐Thio‐D‐xylopyranose Series. Part 3. Preparation of O‐Phenyl and C‐(4‐Hydroxyphenyl)5‐thio‐D‐xylopyranosides.

Abstract

Synthetic Studies in the 5-Thio-D-xylopyranose Series. Part 3.Preparation of O-Phenyl and C-(4-Hydroxyphenyl)5-thio-Dxylopyranosides.-Pyranoses (I), (V), and (VII) are applied in different approaches to obtain the corresponding title O-phenyl and C-(4-hydroxyphenyl) derivatives. The formation of derivatives (III) and (IV) is a result of competitive O-glycosidation and aromatic electrophilic substitution. The sulfur transannular participation pathway becomes predominant when bromide (V) and phenol are treated with ZnCl 2 , affording tetrahydrothiophene (IX). The β-configurated O-phenyl sugar (IV) is found to rearrange readily around normal temperature to produce the more stable β-configurated C-derivative (III). -(BAUDRY, M.; BARBEROUSSE, V.; COLLETTE, Y.; DESCOTES, G.; PIRES, J.; PRALY, J.-P.; SAMRETH, S.; Tetrahedron 54 (1998) 45, 13783-13792; Lab. Chim. Org., CNRS, Univ. Claude Bernard Lyon, F-69622 Villeurbanne, Fr.; EN)