Effect of Tethered, Axial Thioether Coordination on Rhodium(II)-Catalyzed Silyl-Hydrogen Insertion

The effect of tethering a thioether to a rhodium paddlewheel complex are evaluated in diazo-mediated Si–H insertion reactions. This study provides further evidence for the benefits of incorporating thioethers into the rhodium paddlewheel motif. When compared to a non-tethered complex, the in situ carbenoid formation and subsequent Si–H insertion are not impeded by the thioether tether, improves yields by up to 12%, and is more selective for diazo compounds when compared to non-tethered catalysts. Computational modeling of the complexes at the M06-2X/def2-TZVPP level of theory is also presented in order to rationalize the results.