2-Chlorotoluene → 2,2'-Dimethylbiphenyl

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Reaction Steps

To a suspension of magnesium turnings (12.15 grams, 0.5 mole) in THF (150 mL) was added 2-chlorotoluene (50.6 grams, 0.40 mole). The mixture was refluxed for 18 hours, cooled to ambient and added dropwise to a solution of 2-chlorotoluene (44.3 grams, 0.35 mole) and bis(triphenylphosphine)-nickel (II) dichloride (2.0 grams) in THF (250 mL). The reaction mixture warmed upon mixing and was heated to reflux for 4 hours after completion of the addition. The reaction mixture was cooled and quenched by the addition of toluene (400 mL) and a saturated ammonium chloride solution (200 mL). The layers were separated and the organic phase was washed sequentially with 10 percent HCl (200 mL), water (3×100 mL), and then stripped under nitrogen to give a thick oil. The oil was distilled under vacuum to give the product as a fraction boiling in the range of 85° to 90° C. at 1 mm Hg. The yield was 43.40 grams (68 percent of theory) of 2,2'-dimethyl-1,1'-biphenyls containing 93 percent of the 2,2'-isomer and 3.5 percent of other isomers.

Provenance & Evidence