A benzene-bridged divanadium complex-early transition metal catalyst for alkene alkylarylation with PhI(O2CR)2via decarboxylation

Abstract

The synthesis, structure and catalytic activity of a benzene-bridged divanadium complex were comprehensively studied. The reduction of (Nacnac)VCl₂ (1) (Nacnac = (2,6-ⁱPr₂C₆H₃NCMe)₂HC) supported by β-diketiminate with potassium graphite (KC₈) by employing benzene as the solvent allows access to the benzene-bridged inverted-sandwich divanadium complex (μ-η⁶:η⁶-C₆H₆)[V(Nacnac)]₂ (2a), which can catalyze alkene alkylarylation with hypervalent iodine(III) reagents (HIRs) via decarboxylation to generate regioselectively diverse indolinones. Furthermore, the mild nature of this reaction was amenable to a wide range of functionalities on alkenes and HIRs. Mechanistic studies revealed a relay sequence of decarboxylative radical alkylation/radical arylation/oxidative re-aromatization.