in deuterated toluene Me2NAsCl2 and C7H8-d8 were placed in a NMR tube; the tube was evacuatedat -196°C and BCl3 condensed into it; NMR study of the reaction from -100°C to 25°C; mechanism discussed;; not isolated, detected by (11)B-, (13)C-, and (1)H-NMR spectroscopy;;