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Abstract A stepwise copper‐catalyzed boracarboxylation then palladium‐catalyzed Suzuki‐Miyaura cross‐coupling methodology was developed to access 2,3‐diarylpropionic acid derivatives regioselectively by pre‐setting the position of the carboxylic acid in the boracarboxylation reaction. This method provides access to a wide range of aryl and heteroaryl products in up to 80% isolated yield. Pharmaceutical potential was demonstrated by synthesizing a glucagon receptor antagonist drug in three steps (31% overall yield) from commercially available 4‐tert‐butylstyrene. 

Flexible ambiphilic ligand scaffolds have garnered attention in catalysis due to their ability to adopt multiple binding orientations. Recently, several platinum group metal complexes featuring the flexible, ambiphilic b-phosphinoethylborane ligand were reported in the literature; however, the impact of primary coordination sphere ligands and solvent on the properties of the Lewis acidic borane moiety remain underexplored. Rhodium and iridium complexes ligated by 9-borabicyclo[3.3.1]nonanyl-based b- diphenylphosphinoethylborane were studied using a combination of crystallography and 11B NMR spectroscopy. The studies revealed that both the primary coordination sphere and solvent had an impact on the formation of Lewis acid–base adducts. Specifically, inner-sphere Lewis pair formation was dependent on the nature of the X-type ligand bound to the metal center. Similar dependencies were identified with solvents in which Lewis acid interaction was found to correlate with solvent donor number.