Parallel Kinetic Resolution through Palladium-Catalyzed Enantioselective Cycloimidoylation: En Route to Divergent <i>N</i>-Heterocycles Bearing a Quaternary Stereogenic Center
Xilong Wang, Yu Luo, Jing Li, Chaoqin Wang, Qianwen Liu, Yimiao He, Shuang Luo, Qiang Zhu
Abstract
An example of a parallel kinetic resolution catalyzed by palladium to produce enantioenriched five- and six-membered N-heterocycles in one pot was developed. Dihydroisoquinolines and 1H-isoindoles containing a quaternary stereogenic center were obtained from racemic isocyanides in high yields with good enantioselectivities under mild conditions. A 6,6′-dipropyl substituted SPINOL-derived phosphoramidite was used as the chiral ligand for the palladium catalyst, resulting in regiodivergent and stereospecific cycloimidoylation. Density functional theory (DFT) calculations reveal the origin of the regio- and enantioselectivity during the C(sp2)–H imidoylative cyclization process.