Instantaneous SmI2/H2O/amine-mediated reductions in THF

The SmI2-mediated reductions of ketones, imines, and alpha,beta-unsaturated esters have been shown to be instantaneous in the presence of H2O and an amine in THF. The SmI2-mediated reductions are not only shown to be fast and quantitative by the addition of H2O and an amine, but the workup procedures are also simplified. Competing experiments with SmI2/H2O/amine confirmed that alpha,beta-unsaturated esters could be selectively reduced in the presence of ketones or imines. Comparison of analogue ligands showed that nitrogen and phosphorus ligands are superior to oxygen and sulfur ligands in these reductions. The trialkylphosphine 1,2-bis(dimethylphosphino)ethane (DMPE) provided a primary kinetic isotope effect, yielding a k(H)/k(D) of 4.5.