TY - JOUR AU - Diesel, Johannes AU - Cramer, Nicolai PY - 2020/04/29 Y2 - 2024/03/29 TI - Modular Chiral N-Heterocyclic Carbene Ligands for the Nickel-Catalyzed Enantioselective C–H Functionalization of Heterocycles JF - CHIMIA JA - Chimia VL - 74 IS - 4 SE - Scientific Articles DO - 10.2533/chimia.2020.278 UR - https://www.chimia.ch/chimia/article/view/2020_278 SP - 278 AB - N-Heterocyclic carbenes (NHCs) are the ligands of choice in a large variety of transformations entailing different transition metals. However, the number and variety of chiral NHCs suitable as stereo-controlling ligands in asymmetric catalysis remains limited. Herein we highlight the introduction of a modular NHC ligand family, consisting of a chiral version of the widely used IPr ligand. These chiral NHC ligands were applied in the nickel-catalyzed enantioselective C–H functionalization of N-heterocycles. Nickel-NHC catalysis unlocked the stereoselective C–H annulation of 2- and 4-pyridones, delivering fused bicyclic compounds found in many biologically active compounds. Applying a bulky, yet flexible ligand scaffold enabled the highly enantioselective C–H functionalization of pyridones under mild conditions. The introduction of a bulky chiral SIPr analogue enabled the nickel-catalyzed enantioselective C–H functionalization of indoles, yielding valuable tetrahydropyridoindoles. Additionally, pyrrolopyridines, pyrrolopyrimidines and pyrroles were efficiently functionalized, delivering chiral annulated azoles. ER -