The central theme of the Molander group's research is the development of new synthetic methods and their application to the synthesis of organic molecules. The group's focus is to expand and improve the Suzuki coupling reaction for organoboron compounds. Robust, air- and water-stable potassium organotrifluoroborates (R-BF3K), are employed to carry out couplings under relatively mild conditions using non-toxic components.
Greener Routes to Standard Reagents
The preparation of aryl- and heteroaryl potassium trifluoroborate and trihydroxyborate salts has been modified to take advantage of atom-economical boron sources, such as bis-boronic acid (BBA) and tetrakis(dimethylamino)diboron, which allow low catalyst loading and relatively mild reaction conditions. Reactive boronic acid species are generated, and subsequent coupling reactions with these substrates allow greener access to biaryl products.
Improving Transformations with More Robust Reagents
Organotrifluoroborates allow installation of functional groups within a molecule in the place of an existing carbon-boron bond. This allows one to prepare or purchase a simple, functionalized organotrifluoroborate and to elaborate the structure, drawing on the reactivity of the boron species. Some of the transformations carried out to date in this way are outlined below, highlighting the ability to install a cyclopropyl, hydroxymethyl, or nitroso functional group using potassium trifluoroborates.
Novel Reagents and Transformations
Some methods have been developed for the synthesis of novel reagents containing alkyltrifluoroborates, namely potassium aminomethyl-, hydroxymethyl-, and a-alkoxyalkyltrifluoroborates. The synthesis of these structures is outlined below with their applications in cross coupling illustrated.
