in diethyl ether CF3SO3H in Et2O added dropwise over 10 min to cold (-78°C), stirred soln. of Fe complex in Et2O under inert atm., stirred at -78°C for 10 min, PMe3 in Et2O added, stirred at -78°C for 45 min, allowed to warm to room temp.; mixt. of Fe complex and phosphine salt in 63:37 molar ratio pptd., detected by NMR, attempts to separate the two components were unsuccessful, elem. anal.; diene analyzed by GC;