Pd-catalyzed dehydrogenative C–H activation of iminyl hydrogen with the indole C3–H and C2–H bond: an elegant synthesis of indeno[1,2-b]indoles and indolo[1,2-a]indoles

Abstract

Two Pd(OAc)₂-catalyzed sequential C–H activations (C2–H arylation followed by indole C3–H activation with iminyl hydrogen) were employed for the synthesis of indeno[1,2-b]indoles in one pot. This procedure describes a simple way of introducing substituent diversity into this highly important core structure. Indole C2–H activation was also achieved for the synthesis of indolo[1,2-a]indoles.