The development of an enantioselective nickel hydrosilylation catalyst system via multi-substrate screening

Multi-substrate screening (asymmetric hydrosilylation of ketones) comparing the catalytic behaviour of Ru, Ni, Pd, Rh and Ir DIOP-catalyst systems [DIOP = O-isopropylidene-2,3-dihydroxy-1,4-bis(diphenylphosphino)butane] was performed. Initial screening studies revealed that beside the well explored rhodium complexes nickel-based catalysts show interesting selectivity and activity. Mechanistic studies indicate a long induction period in which the active and selective catalyst is formed. [Ni(DIOP)2] which X-ray crystal structure was determined is not active under the applied conditions. Optimisation of the catalyst behaviour concluded from the mechanistic studies led to an improvement of the enantioselectivity by around 20% in comparison to the multi-substrate screening results.

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