Alkylation of Heteroaryl Halides by 2:1 Grignard Reagent/Cu(I) Mixtures.Synthesis of Alkylated Octahydrodibenzophenanhtrolines

Article abstract of DOI:10.1021/jo00226a023

Treatment of 2-bromopyridine,3-bromopyridine,2-chloroquinoline,and 5,8-dichloro-1,2,3,4,9,10,11,12-octahydrodibenzo<1,10>phenanthroline(2) with a fourfold excess of 2:1 Grignard reagent/Cu(I) salt mixtures gives alkylated products in 50-85percent yield.Thus prepared are 2-methylpyridine,2-tert-butylpyridine,3-tert-butylpyridine,2-methylquinoline,2-ethylquinoline,2-tert-butylquinoline, and the dimethyl- and di-tert-butylphenanthrolines(3a) and (3b).Full experimental details are provided for the two phenanthrolines, which are prepared in four steps from o-phenylenediamine and ethyl 1-oxocyclohexane-2-carboxylate in 25-30percent overall yield.