1-Chloronaphthalene → Naphthalene

Participants

Reaction Conditions

Reaction Steps

Under vacuum (0.1 mbar), 3.70 g (150 mmol) of Mg powder was baked out (100-150° C.) and, after cooling, 0.66 g (2 mmol) of 9,10-diphenylanthracene (DA, Aldrich), 50 ml of THF and 2 to 3 drops of ethyl bromide was added. After stirring the mixture for 1 h, a deep-blue solution had formed (formation of the Mg-DA radical anion, see description). To this solution, 0.26 g (2 mmol) of anhydrous FeCl2, 20 ml of THF and 10.2 ml of an 0.49 M solution of MgCl2 in THF (5 mmol) was added, followed by stirring for another 30 min. Thereupon, 13.6 ml (100 mmol) of 1-chloronaphthalene was added dropwise within 30 min, the color of the solution turning from deep-blue to brown, and the solution warming up to 55° C. After 2 h of stirring, the yield of the Grignard compound of 1-chloronaphthalene was 63%, and after 5 h, it was 67% (as determined by acidimetric titration). The protolysis of a 10 ml sample of the solution (total volume 95 ml; cf. Example 1) yielded 0.92 g of naphthalene (corresponding to a yield of 1-C1OH7MgCl of 68%), binaphthyl and no other products (GC analysis).

Provenance & Evidence