Two efficient routes to m-terphenyls from 1,3-dichlorobenzenes

Article abstract of DOI:10.1055/s-1996-4426

In the first route 2,6-dichlorophenyllithium (5), prepared by direct lithiation of 1,3-dichlorobenzene, reacted with aryl Grignard reagents to give m-terphenyls in 57-93% yields; the methodology was extended to substituted 1,3-dichlorobenzenes (i.e. 8 → 10). Also, reaction of 5 with MgCl₂ gave 2,6-dichlorophenyl-magnesium chloride which, on warming, produced the self-capture product tetrachloro-m-terphenyl 7 in moderate yield. In the second route, reaction of 1,3-dichlorobenzene with excess of aryllithium in diethyl ether at room temperature gave the corresponding m-terphenyls in 59-94% yields. Examples are given in which the aryllithium was prepared by three different routes (ArX + Li, ArX + t-BuLi, ArH + BuLi).