An Ir–Pt Catalyst for the Multistep Preparation of Functionalized Indoles from the Reaction of Amino Alcohols and Alkynyl Alcohols

Abstract

The 1,2,4-trimethyltriazolylidene (ditz) ligand allows the preparation of homo- and heterodimetallic complexes of Pt2 and Ir–Pt. These two complexes have been characterized by means of spectroscopic and diffractommetric techniques. The catalytic activity of these complexes, together with that of other Pt-based compounds, has been explored in the cyclization–addition of alkynyl alcohols and indoles. The Ir–Pt complex [{PtI2(py)}(μ-ditz){IrI2(Cp*)}] (py=pyridine; Cp*=pentamethylcyclopentadienyl) allows the combination of an iridium-mediated oxidative cyclization of 2-(ortho-aminophenyl)ethanol to form indoles, with a further step employing a Pt-based multistep reaction that functionalizes indoles. Our results show that the Ir–Pt complex is a very active catalyst in this new multistep preparation of functionalized indoles from the reaction of an amino alcohol with alkynyl alcohols