Cobalt-catalysed acyl silane directed C-H functionalisation of benzoyl silanes

Despite their synthetic utility, practical methods to prepare diversely functionalized aromatic acyl silanes (benzoyl silanes) remain scarce. We herein report that cobalt complexes can successfully engage acyl silanes as weakly coordinating directing groups to catalyse the ortho C-H functionalisation of benzoyl silanes. Under Cp*Co( iii ) catalysis, installation of allyl or amido functionality at the 2-position of benzoyl silanes was achieved, while reaction with internal alkynes led to a desilylative annulation to afford indenone scaffolds. A Co( ii )/dppp catalytic system was also investigated to achieve the acyl silane directed hydroarylative cyclisation of 1,6-enynes to access unique benzoyl silane derivatives. Acyl silanes can be engaged as weakly coordinating directing groups in cobalt catalysed C-H functionalisation reactions to prepare benzoyl silanes that are highly amenable to subsequent synthetic manipulations yet inaccessible via existing methods.