Most nucleophilic substitutions take place by the s n 2 pathway just discussed. Skip to main content. Webthis alternative mechanism is called the sn1 reaction, for substitution, nucleophilic, unimolecular.

The key to substitution and elimination reactions is to have a good leaving group, an electronegative atom or functional group that is weakly attached to carbon and. The reaction is favored when carried out with an unhindered substrate and a negatively. Webstereochemistry of an sn1 reaction and how it relates to the sn1 mechanism.