Examination of N,N-dimethylbenzylamine as a substrate for ruthenium-catalysed C-H (thio)amidation: A mass spectrometry and DFT directed study

Key steps in the potential application of N,N-dimethylbenzylamine, a widely used substrate in organometallic chemistry, in ruthenium-catalysed C-H (thio)amidation have been examined. In particular, a cationic cyclometalated ruthenium(II) complex has been synthesised and characterised by X-ray crystallography and its insertion reactions with phenyl iso(thio)cyanate studied using electrospray ionisation high-resolution mass spectrometry (ESI-HRMS) and Density Functional Theory (DFT) calculations. The ruthenium(II) catalysed process proved to be inferior to synthesising (thio)amides by ortho-lithiation, iso(thio)cyanate insertion hydrolysis, and provide insights into mechanisms that are consistent with proposals reported in examination of 2-phenylpyridine as the substrate.