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 base leads to the migration of the N'-aryl substituent from N to C in a 'non-classical' intramolecular nucleophilic aro-matic substitution reaction. Both electron-rich and electron-poor rings migrate successfully. A new quaternary stereo-genic centre 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.