Synthesis of multiply functionalized benzenes via ruthenium-catalyzed cycloaddition of diiododiynes

Highly functionalized benzenes were precisely synthesized via multi-step processes consisting of ruthenium-catalyzed [2+2+2] cycloaddition of diiododiynes with an ethynylboronate or terminal alkynes, and subsequent chemo- and regio-selective palladium-catalyzed C-C bond-forming reactions of the resulting cycloadducts. The sequential cycloaddition/coupling process was applied to the synthesis of oligo(p-phenylene ethynylene)s. (c) 2007 Elsevier Ltd. All rights reserved.