Scalable Synthesis of β-Lactamase Inhibitor QPX7728 by Sequential Nickel-Catalyzed Boron Insertion into a Benzofuran Substrate and Enantioselective Cyclopropanation of the Resulting Vinylboronate

We report the scalable, high-yielding, and highly selective synthesis of the β-lactamase inhibitor QPX7728 featuring two key synthetic steps: nickel-catalyzed boron insertion of benzofuran 1 followed by enantioselective cyclopropanation of the resulting cyclic vinylboronate 2. The identification of the key reagents (catalyst and chiral auxiliary) for both steps relied on the use of high-throughput experimentation. Further optimization allowed for the cost-effective and scalable production of QPX7728.