Synthesis of Chiral δ-Aminoboronic Esters by Enantioselective Hydrogenation of 1,2-Azaborines

We describe herein an iridium-catalyzed highly diastereo- and enantioselective hydrogenation of 1,2-azaborines ac- cessing δ-aminoboronic esters of potential biological importance. This method represents the first enantioselective hydrogenation of boron-containing heteroarene and features a diverse substitution pattern and wide scope. The synthetic utility of our method was demonstrated by the synthesis of (–)-Phenibut and the formal synthesis of (+)-3-PPP and Fluvirucinine A1.