Et3N in dichloromethane byproducts: Et3NH-AlCl4; to borenium cation made in situ (in Schlenk, to soln. Et2N (CH2Cl2) added Cl4CatBCl, AlCl3; stirred) at 20°C arene added (CH2Cl2); excessEt3N added; pinacol added; stirred for 4 h;; (11)B (1H) NMR; volatiless remowed under vac; extracted (hexane); filtered through silica; removal of solvent;;