Four Tandem C-H Activations: A Sequential C-C and C-O Bond Making via a Pd-Catalyzed Cross Dehydrogenative Coupling (CDC) Approach

An unprecedented aroylation at the ortho C-H bond with respect to a directing group has been accomplished via a Pd(II)-catalyzed cross dehydrogenative coupling approach using alkylbenzene as the synthetic equivalent of an aroyl moiety. The reaction proceeds through sequential C-C and C-O bond making at the expense of four consecutive C-H bond cleavages (three sp(3) benzylic C-H's and one sp(2) arene C-H) to selectively install an aroyl functionality at the proximal site of substrates containing various directing groups.