Preparation of bipyridyl derivatives via α-lithiation of pyridyl phenyl sulfoxides, substitution with electrophiles and cross-coupling reactions with Grignard reagents

Abstract

Treatment of 2-, 3-, and 4-pyridyl phenyl sulfoxides with lithium diisopropylamide (LDA), subsequently with electrophiles gave the corresponding sulfoxides regioselectively bearing substituents at the α-position in the pyridine ring. These sulfoxides were converted to the substituted bipyridyls in high yields via cross-coupling reactions with pyridyl Grignard reagents (PyMgBr).