Some Reactions of 1-Lithio-2-phenyl-1,2-dihydropyridine. IV. Synthesis of β-Substituted Pyridines

Abstract

Alkylation of the ambident anion 1-lithio-2-phenyI-1,2-dihydropyridine (1a) has been investigated. A direct method for introducing an alkyl or arylalkyl group into the β-position of pyridine is described. Reaction of 1a with styrene oxide or ethylene oxide afforded 2-(2-phenyl-5-pyridyl)-1-phenylethanol (10) and 2-(2-phenyl-5-pyridyl)ethanol (11), respectively. With N-benzylideneaniline the unexpected 2-phenyl-5-benzylpyridine (7) was obtained. When 1a was allowed to react with perhalomethanes, conditions conducive to carbene formation, bis(6-phenyl-3-pyridyl)methane (12) and 6,6′-diphenyl-3,3′-dipyridyl (13) were obtained. Mechanisms for the formation of 7, 12, and 13 are discussed. Reactions of 1a with other electrophilic substrates are described.