A mixture of 12-bromo-2,10-dichloro-12H-5,7-dioxa-dibenzo[a,d]cyclooctene (900 mg, 2.5 mmol), 2-bromoethanol (3.75 g, 30 mmol) and potassium carbonate (1.0 g, 7.2 mmol) in dichloromethane (10 mL) was heated at 120° C. for 4 h. The reaction mixture was concentrated in vacuo, added water (25 mL) and the product extracted with ethyl acetate (3×25 mL). The combined organic phases were dried (MgSO4), filtered and evaporated to give 832 mg (82%) of 12-(2-bromo-ethoxy)-2,10-dichloro-12H-5,7-dioxa-dibenzo[a,d]cyclooctene.
