C-GLYCOSIDE SYNTHESIS BY PALLADIUM-CATALYZED IODOAGLYCON GLYCAL COUPLING

Efficient coupling of iodo derivatives of anthracycline aglycons with furanoid and pyranoid glycals has been achieved with use of stoichiometric portions of the reactants in the presence of catalytic amounts of palladium(II) acetate and a tertiary amine in dimethylformamide solution at room temperature. This procedure, which occurs regio- and stereospecifically, is an effective route to aryl C-glycosides. Demonstration of the efficacy of this palladium-mediated coupling reaction was illustrated by its use in a one-pot four-step sequence that produced the anthracycline C-glycoside 4-[2ʹ-deoxy-3ʹ,5ʹ-diacetyl-β-D-ribo(=arabino)-furanosyl]-8-ethyl-1-methoxybenzo[d]naphtho[l,2-b]pyran-6-one in 94% isolated yield. © 1990, American Chemical Society. All rights reserved.