SOLID-PHASE SYNTHESIS OF BIARYLS VIA THE STILLE REACTION

The solid-phase synthesis of biphenyls by heterogenous cross-coupling of trialkylphenylstannanes with aryl electrophiles is described. Tribu tylphenyltin attached by an amide bond to the Rink amide resin undergo es palladium-catalyzed coupling with aryl triflates and aryl iodides t o produce after acid cleavage 4-biphenylacetamide in 3-15% yield. 4-Io dophenylacetic acid attached to the Rink amide resin by an amide bond also undergoes heterogeneous palladium-catalyzed coupling with trialky lphenyltins to give after acid cleavage of the support 4-biphenylaceta mide in 21-33% yield. 4-Iodobenzylbromide was then attached to the pho tocleavable (2-nitrophenyl)dithio]-1-oxopropyl]phenylacetamide (NpSSMp act) resin through the formation of a thioether bond. Both substituted and unsubstituted trimethylphenyltins were shown to undergo palladium -catalyzed Stille coupling with the resin bound aryl iodide to give af ter photolytic cleavage biphenyls containing no residual ual amide, ca rboxylic acid, or alcohol appendages.