Rational design of a facially coordinating P,N,N ligand for manganese-catalysed enantioselective hydrogenation of cyclic ketones

Authors would like to thank the University of St Andrews, combined with the EPSRC Centre for Doctoral Training in Critical Resource Catalysis (CRITICAT) for financial support [PhD studentship to CO; Grant code: EP/L016419/1], and the EaSI-CAT programme PhD studentship to AG].DFT calculations on the full catalytic cycle for manganese catalysed enantioselective hydrogenation of a selection of ketones have been carried out at the PBE0-D3PCM//RI-BP86PCM level. Mn complexes of an enantiomerically pure chiral P,N,N ligand have been found to be most reactive when adopting a facial coordination mode. The use of a new ligand with an ortho-substituted dimethylamino-pyridine motif has been calculated to completely transform the levels of enantioselectivity possible for the hydrogenation of cyclic ketones relative to the first-generation Mn catalysts. In silico evaluation of substrates has been used to identify those likely to be reduced with high enantiomer ratios (er), and others that would exhibit less selectivity; good agreements were then found in experiments. Various cyclic ketones and some acetophenone derivatives were hydrogenated with er's up to 99:1.Publisher PDFPeer reviewe