Chlorobenzene → Biphenyl

Participants

Reaction Steps

Ali et al., Tetrahedron, vol 48 (1992), pp. 8117-8126 discloses Suzuki-type cross-coupling reactions of arylboronic acids with pi-electron deficient heteroaryl chlorides (chloropyridines, chloropyrimidines, and chloropyrazines, chloroquinolines). These authors state, "It is widely accepted that palladium-catalyzed cross coupling reactions of arylboronic acids, and indeed of other organometallic species, proceed best with aryl or heteroaryl bromides or iodides, and either poorly, or more commonly, not at all with the corresponding chlorides." These investigators confirmed early literature reports that reaction of phenylboronic acid with either chlorobenzene or 3-chloropyridine in the presence of tetrakis(triphenylphosphine) palladium failed to prcoduce any coupled product. Using Pd(bis-1,4-(diphenylphosphino)butane)Cl2, however, they were able to get chlorobenzene to react to give 28% of biphenyl, and 3-chloropyridine was converted to 3-phenylpyridine in 71% yield. Among 2-chloropyridines, the reaction tolerated some (3-nitro, 5-chloro) but not other (3-OH, 3-CONH2) substituents.

Provenance & Evidence