Solvent-free catalytic enantioselective C–C bond forming reactions with very high catalyst turnover numbers

Rhodium(II)-catalyzed reactions of donor/acceptor carbenoids can be achieved with catalyst loadings as low as 6 × 10−7 mol equivalents when the reactions are conducted in the absence of solvent. ReactIR studies demonstrate that donor/acceptor carbenoids are ideal for achieving high catalyst turnover numbers due to the rapid reactions of their diazo precursors and the enhanced selectivity of this class of carbenoids.