Rhodium Asymmetric Hydrogenation Observed during its Exponential Growth Phase

The field of asymmetric hydrogenation grew rapidly after the early 1970s. What had begun as a demonstration of enantioselectivity in catalysis by purely chemical means became an important tool both for academic research and for industry. Right from the beginning, a question was posed as to how relatively simple catalysts were able to generate such unprecedented levels of stereoselectivity. This article provides an account of Oxford-based contributions to the field of rhodium complex catalyzed asymmetric hydrogenation from 1978 onward, when the initial realization of this practical catalytic method for synthesis of single enantiomers had already been achieved. NMR-based experiments that help to elucidate the structures of reactive intermediates in catalysis are strongly emphasized here and linked to the present understanding of the mechanism of a reaction that has sustained interest over the intervening years.