Stereospecific Intramolecular Arylation of 2- and 3‑Pyridyl Substituted Alkylamines via Configurationally Stable α‑Pyridyl Organolithiums

Treatment of N′-aryl urea derivatives of enantiomerically enriched α-(2-pyridyl) and α-(3-pyridyl)­alkylamines with a base leads to the migration of the N′-aryl substituent from N to C in a ‘nonclassical’ intramolecular nucleophilic aromatic substitution reaction. Both electron-rich and -poor rings migrate successfully. A new quaternary stereogenic center is formed adjacent to the pyridine ring with high stereospecificity, even when the intermediate anion is a presumably planar 2-picolyllithium. Base hydrolysis of the urea gives enantiomerically enriched α-pyridylalkylamines.