Low-valent TiII species have typically been synthesized by the reaction of TiIV halides with strong metal reductants. Herein we report that TiII species can be generated simply by reacting TiIV imido complexes with 2 equiv of alkyne, yielding a metallacycle that can reductively eliminate pyrrole while liberating TiII. In order to probe the generality of this process, TiII-catalyzed alkyne trimerization reactions were carried out with a diverse range of TiIV precatalysts.
Bibliographical noteFunding Information:
Financial support was provided by the University of Minnesota (start-up funds, Heisig/Gleysteen fellowship for T.A.W.), the ACS Petroleum Research Fund (ACS-PRF 54225-DNI3) and the National Institutes of Health (1R35GM119457). Departmental equipment was purchased via grants from the NSF (MRI 1224900) (Bruker-AXS D8 Venture diffractometer) and the NIH (S10OD011952) (NMR Facility) with matching funds from the University of Minnesota.