General Procedures. 5-Hexynoyl chloride was prepared from 5-hexyn-1-01 (Farchan Laboratories) as described in the literature. 8 2-(Trifluoromethy1) phenol and dibromodifluoromethane were purchased from Aldrich Chemical Co. Tetrahydrofuran (THF) and diethyl ether were distilled from sodium benzophenone ketyl prior to use. Dimethylformamide (DMF) was distilled from calcium hydride prior to use. ...