Efficient, catalytic, asymmetric crossed acyloin condensations

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178 years after the Benzoin Condensation (BC) was discovered, a general, small molecule catalytic system for the cross-coupling of two different aldehyde molecules to generate enantioenriched α-hydroxy ketone products remains beyond our reach. We intend to instigate a systematic research programme aimed at addressing several challenges which have (in our view) stymied the progress of acyloin resp. benzoin chemistry over the past two centuries. Preliminary data and an analysis of models strongly indicate that a novel bifunctional chiral organocatalyst system developed in our groups would be capable of promoting a variety of asymmetric cross benzoin condensations (ACBC reactions) where other systems seem to have failed. The hydrogen-bond donating catalyst will allow for substrate activation and should simultaneously control (stereo)selectivity. A testable selectivity model and strategy has been identified which will allow the exploitation of this discovery and the development of modified 2nd generation catalysts to better promote these transformations, which for the most part are completely beyond the scope of benchmark catalyst technology. A further extension to broaden the scope of the reaction to the eventual goal of using ketones as electrophilic substrates by the means of cooperative catalysis has been introduced. We want to design and prepare a novel class of chiral organocatalyst capable of promoting synthetically useful asymmetric crossed acyloin reactions of wide scope, for which no general and efficient enantioselective catalytic system is currently available.