Arylation de glycals catalysée par les sels de palladium: nouvelle synthèse de <i>C</i>-glycosides

Abstract

The arylation of peracetylated glycals catalyzed by palladium salts provides a new synthesis of C-glycosides. The title reaction is applied to several aromatic compounds, including fluoro and nitro derivatives. The regioselectivity of the reaction with respect to the aromatic nucleus is explained by the formation of an arylpalladium directly from the aromatic compound and the salt. A two-step mechanism, involving syn-addition of the arylpalladium to the glycal double bond, followed by a syn-elimination is proposed and discussed.