In a 200-ml. round-bottomed flask fitted with an efficient reflux condenser are mixed 31.4 ml. (38 g., 0.27 mole) of freshly distilled benzoyl chloride, 28.2 ml. (25 g., 0.35 mole) of tetrahydrofuran (Note 1), and 5 g. of freshly fused zinc chloride. A vigorous reaction begins immediately, and after a few seconds, when the mixture starts to boil, external cooling is applied with an ice bath. After the initial reaction has subsided, the mixture is heated on a steam bath for 15 minutes, cooled, and dissolved in 100 ml. of benzene. The benzene solution is washed with 100 ml. of a 5% solution of sodium chloride and then with 100 ml. of a saturated solution of sodium bicarbonate. The benzene layer is dried over anhydrous sodium sulfate and fractionally distilled from a modified Claisen flask.

The product is collected at 140–143°/5 mm., 132–135°/2.5 mm.; n_D25 1.5176 (Note 2). The yield is 45–48 g. (78–83%).