Diethyl Ether → 8-Chloro-1,2,3,4-tetrahydronaphthalen-2-one

Participants

Reaction Conditions

Reaction Steps

To a slurry of 46.5 gm (0,348 mole) AlCl3 in 400 mL dichloromethane at -78° C. was added a solution of 32.76 gm (0.174 mole) of the previously prepared o-chlorophenylacetyl chloride in 100 mL dichloromethane dropwise over 1 hour. The dry ice/acetone bath then was replaced with an ice/water bath and ethylene was bubbled into the reaction mixture during which time the temperature rose to 15° C. The ethylene addition was discontinued at the end of the exotherm and the reaction mixture was stirred at about 5° C. for 4 hours. Ice was then added to the reaction mixture to destroy aluminum complexes. Upon termination of the exotherm, the reaction mixture was diluted with 500 mL of water and stirred vigorously until all solids had dissolved. The phases were separated and the organic phase was washed with 3×400 mL 1N hydrochloric acid and 2×400 mL saturated aqueous sodium bicarbonate. The remaining organic phase was then dried over sodium sulfate and concentrated in vacuo to give a pale orange residue. The residue was dissolved in 1:1 hexane:diethyl ether and was poured over a flash silica column which was then eluted with 1:1 hexane:diethyl ether to give a light yellow residue which was crystallized from 4:1 hexane:diethyl ether to give 10.55 gm of the title compound. NMR (CDCl3): 7.5-7.2 (m, 3H), 3.7 (s, 2H), 3.3-3.0 (t, J=7 Hz, 2H), 2.8-2.4 (t, J=7 Hz, 2H). MS: 180(60), 165(9), 138(100), 117(52), 115(50), 103(48), 89(20), 76(25), 74(18), 63(30), 57(9), 52(28), 51(20), 42(6), 39(32). IR(nujol mull): 2950 cm-1, 2927 cm-1, 1708 cm-1, 1464 cm-1, 1450 cm-1, 1169 cm-1, 1141 cm-1.

Provenance & Evidence