Synthesis of Densely Substituted Pyridine Derivatives from 1-Methyl-1,3-(ar)enynes and Nitriles by a Formal [4+2] Cycloaddition Reaction
Dandan He, Bowen Wang, Kanghui Duan, Yang Zhou, Meng Li, Huanfeng Jiang, Wanqing Wu
Abstract
An attractive method for assembling densely substituted pyridine derivatives from 1-methyl-1,3-(ar)enynes and nitriles via a formal [4+2] cycloaddition has been established. The well-balanced affinities of two alkali metal salts enable C(sp3)–H bond activation and excellent chemo- and regioselectivities. Experimental studies revealed that nitrile functions only as a partial nitrogen source for pyridine synthesis, and the addition of a metalated imine intermediate to an intramolecular alkyne is the rate-limiting step.
Topics & Concepts
ChemistryCycloadditionPyridineIntramolecular forceNitrileAlkyneImineMedicinal chemistryCombinatorial chemistryOrganic chemistryCatalysisCatalytic C–H Functionalization MethodsCyclopropane Reaction MechanismsSynthesis and Catalytic Reactions