2-Pyridyl Sulfoxide Directed Pd(II)-Catalyzed Regioselective C2- Arylation/Alkenylation of Indoles

Abstract

The present study reports a Pd(II)-catalysed regioselective C2-arylation and alkenylation of indoles using iodoarenes and activated/unactivated alkenes, respectively, directed by 2-pyridyl sulfoxide at the C3-position of indole for the first time. This additive-free approach proceeds under oxidative conditions, using silver oxide as the oxidant, and furnishes the biologically important C3-thia-2-functionalized indoles in moderate to very good yields. Notable features of this protocol include a readily cleavable/amenable directing group, compatibility with diverse functional groups, broad substrate applicability, excellent regioselectivity, good scalability, and promising potential for late-stage functionalization.