Research of bifunctional catalysts for C-C bond forming reactions

Abstract

Bifunctional catalysis is a well understood phenomenon in nature, with enzymes frequently using two (or more) functional groups to accomplish selective transformations on a suitable substrate. It is becoming clear however, that bifunctional catalysis is not merely of interest to explain or mimic biological efficiency and rate enhancement, but is a viable design principle for the development of new molecular catalysts. In this thesis we have prepared achiral amino-boronic acid compounds with different scaffold structures based on general structures 1 and 2.(^5). although these compounds did not show any reactivity towards the MBH and aza-MBH reaction, they were very successful as catalysts for the aldol reaction. For this reaction it was possible to select the wanted product (aldol or chalcone product) using the same bifunctional catalyst only by changing the solvent. Also with hydroxyacetone some excellent results were gained with yields between 49 to 97% for both aromatic and aliphatic aldehydes in very high regioselectivity. (see Equation)