| Boronic acids possess significant biological, medicinal and synthetic applications. Herein, N,N-diethanolaminomethyl polystyrene (DEAM-PS) is shown as a valuable solid support to facilitate the derivatization of functionalized boronic acids. This resin has led to the synthesis of many new boronic acids that are not otherwise easy to obtain using solution phase methods. UV spectroscopic studies indicated that boronic acid immobilization and cleavage occur under a rapidly reached equilibrium. The DEAM-PS boronate linkage is stable to a wide range of chemistries under anhydrous conditions. Numerous boronic acid derived amines, anilides, and ureas can be synthesized. Multi-component and sequential reactions are also possible. DEAM-PS supported boronic acids can further be employed in a borono-Mannich resin-to-resin transfer reaction (RRTR) yielding arylglycine derivatives.; A solution phase methodology for the first report of an intramolecular Petasis borono-Mannich reaction has shown promising results. Cyclization with glyoxylic acid is possible for the formation of a six-membered ring product. |
