Palladium‐Catalyzed Atroposelective Suzuki–Miyaura Coupling to Construct Axially Chiral Tetra‐Substituted α‐Boryl Styrenes

• Published in: Advanced science 2024-06, Vol.11 (24), p.e2309706-n/a
• Main Authors: Li, Xiaorui, Kong, Lingyu, Yin, Shuxin, Zhou, Hengrui, Lin, Aijun, Yao, Hequan, Gao, Shang
• Format: Article
• Language: English
• Subjects: atroposelective synthesis; axially chiral tetra‐substituted styrenes; gem‐diboryl alkenes; Ligands; Palladium; palladium‐catalyzed; Suzuki–Miyaura coupling
• ISSN: 2198-3844; 2198-3844
• DOI: 10.1002/advs.202309706

Palladium‐catalyzed Suzuki–Miyaura (SM) coupling is a valuable method for forming C─C bonds, including those between aryl moieties. However, achieving atroposelective synthesis of axially chiral styrenes via SM coupling remains challenging. In this study, a palladium‐catalyzed atroposelective Suzuki–Miyaura coupling between gem‐diborylalkenes and aryl halides is presented. Using the monophosphine ligand Me‐BI‐DIME (L2), a range of axially chiral tetra‐substituted acyclic styrenes with high yields and excellent enantioselectivities are successfully synthesized. Control experiments reveal that the gem‐diboryl group significantly influences the product enantioselectivities and the coupling prefers to occur at sites with lower steric hindrance. Additionally, the alkenyl boronate group in the products proves versatile, allowing for various transformations while maintaining high optical purities. A palladium‐catalyzed chemoselective and atroposelective Suzuki–Miyaura coupling between aryl halides and gem‐diboryl alkenes is developed. Various tetra‐substituted axially chiral α‐boryl styrenes are constructed with excellent chemoselectivity and enantioselectivity. Control experiments indicate the coupling prefers to occur at sites with lower steric hindrance. The alkenyl boronate group in the products proves versatile, allowing for various transformations with excellent enantioretention.