Abstract

The long-term collaboration with Prof. John R Jones has enabled the development or discovery of a range of one-step ³H- and ²H-labelling approaches. These include; (a) RhCl₃.3H₂O and COD.Ir.Acac catalysed ortho-exchange of aromatic acids, amides, benzylamines, anilides, sulphonamides, etc, using isotopic water as the donor in DMF or DMA solution, (b) the COD.Ir.F₆Acac catalysed ortho-labelling of anilines, benzylamines and other N-heterocyclics using isotopic hydrogen gas in DMA at RT, (c) the α- and β-labelling of piperidines, piperazines and other secondary amines using catalytic Ru(CO)₆Cl₂ or (C₆H₅)₂RuCl₂ with deuterium oxide in DMSO, (d) the α-labelling of pyridines and other N-heteroaromatics using rhodium and ruthenium heterogeneous catalysts with isotopic hydrogen gas in THF at RT and (e) the preparation of an efficient and clean polystyrene-based Ir(I) phosphine catalyst for the labelling of aromatic esters, aromatic ketones, sulphones, amides, anilides, etc, using isotopic hydrogen gas in dichloromethane at RT.  Latterly, screening for the terminal-methylene labelling of 1-monosubstituted and 1,1-disubstituted alkenes has provided new catalytic systems for this transformation. In addition, it has provided evidence for the significance of secondary metal alkyl intermediates in the general mechanism of catalytic alkene exchange and reduction. These studies were facilitated by the application of a ³H-NMR cryoprobe.

Keywords: isotope-exchange, ortho-labelling, catalysis, alkene-exchange, hydrogenation-mechanism, deuteration, tritiation.