Selective organometallic syntheses from molecular pools

Abstract

A new methodology is described, consisting of the use of molecular pools in palladium-catalyzed sequential processes occurring under mild conditions with high selectivity. These reactions involve palladacycle formation from aryl iodide, palladium, and norbornene, the latter behaving as a second catalyst that is first incorporated into the metallacycle and expelled at the end of the process. Selective alkylation or arylation of the arene nucleus occurring by oxidative addition/reductive elimination of palladacycles are coupled, after norbornene expulsion, with C-H or C-C bond-forming reactions such as hydrogenolysis, olefin insertion, arylboronic coupling, etc. The variety of possible combinations offers a powerful tool for the selective synthesis of unusual and not readily accessible aromatics.