ELECTROSTATIC ACTIVATION OF NUCLEOFUGES - CATIONIC LEAVING GROUPS

The substitution of two chlorine atoms by dimethylaminopyridino groups in PCl3 (1), MeOPCl2 (2), and MeOP(O)Cl2 (3) yields phosphorus derivatives that are dicationic (1 and 2) or monocationic (3). These molecules are highly activated toward nucleophilic attack. For the first time, in nucleophilic reactions a cationic group is the leaving group. In fact, the nucleofuge derived from 3 is a better leaving group than the trifluoromethane sulfonate ion.