Final Report Summary - DAUBOR (Design and Applications of Unconventional Borylation Reactions)
Traditionally, the methods to form carbon-boron bonds have mostly been based on the electrophilic nature of boron due to its empty p-orbital. Changing the electrophilic nature of boron, by developing methods to generate and use nucleophilic boron species, opens new ways to introduce boron atoms into organic molecules. This concept has been the driving force of DAUBOR. Inspired by unsolved problems found in the synthesis of bioactive molecules, we have searched for unconventional ways to activate boron compounds to efficiently prepare valuable synthetic intermediates. We have invested particular effort in the synthesis of chiral molecules containing sp3 carbon-boron stereocenters, which are difficult to access by known methods. Through the generation of nucleophilic boron species, we have successfully developed new stereoselective methods for the preparation of sp3-rich building blocks that are present in bioactive natural products or drugs such as cyclopropanes, cyclobutanes, benzylic derivatives, allylic alcohols, allenes, and aminoboronates. Through DAUBOR we have prepared novel boron-containing molecules that were not accessible using conventional borylation reactions. In doing so, we are not only providing new tools for the preparation of valuable synthetic intermediates but we also increasing the chemical space for potential biological applications.