Journal of the American Chemical Society, Vol.134, No.45, 18534-18537, 2012
Three Hydrogen Bond Donor Catalysts: Oxyanion Hole Mimics and Transition State Analogues
Enzymes and their mimics use hydrogen bonds to catalyze chemical transformation's. Small molecule transition : state analogues of oxyanion holes have been characterized by computations, gas phase IR and photoelectron spectroscopy, and determination of their binding constants in acetonitrile. A new class of hydrogen bond catalysts is proposed (donors that can contribute three hydrogen bonds to a single functional group) and demonstrated in a Friedel-Crafts reaction. The employed catalyst was observed to react 100 times faster than its rotamer that can employ only two hydrogen bonds. The former compound also binds anions more tightly and was found to have a thermodynamic advantage.