Chiral ligands have played a vital role in the development of asymmetric catalysis. Past two decades have witnessed rapid growth in the development of different classes of chiral ligands and their applications leading to the evolution of numerous useful methodologies. BINAP, QUINAP, and PINAP are few ligands to fall under an important category of chiral ligands namely atropsiomeric ligands. For C2-symmetric atropisomeric ligands like BINAP, it is relatively simpler to understand the mode of enantio-induction because of reduced numbers of diastereomeric complexes. However, C1-symmetric atropisomeric ligands lack in symmetry and it becomes challenging to understand the way steric parameters affect the chiral pocket. A protocol demonstrating the effect of incremental change in the position of substituents affecting the chiral pocket in C1-symmetric atropisomeric Stack-Ligands will be presented. The study reveals the first axially chiral P,N-ligand for highly enantioselective synthesis of organoboranes via a Cu catalyzed enantioselective borylation of Michael acceptors. Moreover, a complementary ligand was synthesized in the process to overcome the limitations of parent Stack-Ligand demonstrating the tunability of Stack-Ligands. Mechanistic studies revealing the potential nature of catalytically active metal-ligand complex will also be discussed.

Configuration sampling with 6,5-atropisomeric stack-ligands and application in enantioselective synthesis of organoboranes

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.