Sn2 Mechanism of Stoichiometric Substitution Reactions

Sn2 substitution reactions of alkyl halides with hard nucleophiles such as alkyl anions can be achieved most readily with the aid of organocopper chemistry [95]. Sn2 reactions with epoxides and aziridines are also synthetically useful [96]. The 

The proposed participation of a Cu intermediate is based on an analogy with the chemistry of lithium diorganoaurate(I), R2Au Li [102, 103]. Recent crystallographic data for Cu species [104] have further supported the similarity between Au and Cu [105]. 

---