Synthesis of biaryls via palladium-catalyzed [2+2+2] cocyclization of arynes and diynes: Application to the synthesis of arylnaphthalene lignans

Abstract

A novel method for construction of biaryls via palladium(0)-catalyzed [2 + 2 + 2] cocyclization of diynes and arynes was developed. By this [2+2+2] cocyclization, various arylnaphthalene derivatives, including a sterically hindered 2,2′-disubstituted-1,1′ naphthyl, can be constructed by virtue of a variety of combinations of diynes and aryne precursors. Using this [2+2 + 2] cocyclization as a key step, the total syntheses of natural arylnaphthalene lignans, taiwanin C, taiwanin E, and dehydrodesoxypodophyllotoxin were achieved. © 2007 Wiley-VCH Verlag GmbH & Co. KGaA.