Ligand design for Rh( iii )-catalyzed C–H activation: an unsymmetrical cyclopentadienyl group enables a regioselective synthesis of dihydroisoquinolones

Abstract

We report the regioselective synthesis of dihydroisoquinolones from aliphatic alkenes and O-pivaloyl benzhydroxamic acids mediated by a Rh(iii) precatalyst bearing sterically bulky substituents. While the prototypical Cp∗ ligand provides product with low selectivity, sterically bulky Cpt affords product with excellent regioselectivity for a range of benzhydroxamic acids and alkenes. Crystallographic evidence offers insight as to the source of the increased regioselectivity. © 2014 The Royal Society of Chemistry.