All the reactions were followed in dichloromethane.
It has a very low permittivity (D9.08) [9], a very low
donor number (DN2) and a good acceptor number
(AN20.4) [10]. Alkali halides and Me4NBr are insoluble
in this solvent; salts with large aliphatic or aromatic
cations are soluble, but a large fraction of the
salts will exist as ion pairs