The Palladium-Catalyzed Glycosylation of Halotropones.

A range of mono- and disaccharides, including glucose derivative 10 , has been cleanly coupled, in the presence of a Pd catalyst, with various halogenated and structurally distinctive tropones, including "parent" compound 11 , to afford the corresponding α- and β-anomeric forms of the tropolone glycosides, e.g., 12 and 13 , respectively. Varying the ligand used influences the anomer distribution significantly and such that either the α- or β-form predominates. Notable chemo- and regioselectivities are observed when dihalogenated troponoids are employed as coupling partners.