N‑Sulfonyl bisimidazoline ligands and their applications in Pd(II)-catalyzed asymmetric addition toward α‑tertiary amines
Jia-Yin Wang, Meng-Wei Li, Meng-Fan Li, Wen-Juan Hao, Guigen Li,* Shu-Jiang Tu,* Bo Jiang*
A new class of chiral N-sulfonyl bisimidazoline (Bim) ligands have been designed, prepared and applied in Pd(II)-catalyzed asymmetric addition of arylboronic acids to isatin-derived N-Boc ketimines. The combination of Pd(OCOCF3)2 and N-tosyl Bim ligand shows high catalytic activity and excellent asymmetric induction, enabling asymmetric addition to offer α-tertiary amines with generally good to high yields and excellent enantioselectivity (up to 96% yield, 96% ee). This asymmetric Pd(II)-catalysis can tolerate air conditions, providing a practical and operationally simple protocol toward the construction of enantioenriched α-tertiary stereocenter.
Org. Lett. 2018, 20, 6616-6621
Highlighted by Synfacts (2018, 14(12), 1279, DOI: 10.1055/s-0037-1611321)
