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 alpha-(2-pyridyl) and alpha-(3-pyridyl)alkylamines with a base leads to the migration of the N'-aryl substituent from N to C in a 'nonclassical' intramolecular nudeophilic 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 alpha-pyridylalkylamines.