How can I determine SN2 or SN1?

Question

How can I determine SN2 or SN1?

1 Answer

Impact of this question

6272 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2018-04-18T19:54:26

There are many things you can look at to determine if a reaction is $S_{N} 1$ $S_N1$ or $S_{N} 2$ $S_N2$ .

Explanation:

The first thing you can look after is how large the substrate is. If we have a leaving group on a tertiary carbon atom the reaction would most likely be an $S_{N} 1$ $S_N1$ reaction because of steric hindrance. If the leaving group sits on a methyl group it would most likely be an $S_{N} 2$ $S_N2$ reaction.

Examples of these would be:

$S_{N} 1$ $S_N1$ reaction:

![https://www.masterorganicchemistry.com]( useruploads.socratic.org )
Here you can see that the leaving group $(B r)$ $(Br)$ is sitting on a tertiary carbon.

$S_{N} 2$ $S_N2$ reaction:

![https://www.masterorganicchemistry.com]( useruploads.socratic.org )
Here you can see that the leaving group $(B r)$ $(Br)$ is sitting on a methyl group.

Of course, this is not always the case (depending on solvent and nucleophile). The biggest indicator might be the nucleophile and the solvent.

In an $S_{N} 1$ $S_N1$ reaction, the nucleophile is a neutral ( $H_{2} O$ $H_2O$ or $R - O H$ $R"−"OH$ ) with a polar protic solvent (e.g. alcohols). In an $S_{N} 2$ $S_N2$ reaction, the nucleophile is negatively charged ( $O^{-}$ $O^−$ , $C N^{-}$ $CN^−$ ...) with a polar aprotic solvent (e.g. DMSO, acetone).

Science

Math

Humanities

... and beyond

How can I determine SN2 or SN1?

1 Answer

Explanation:

Related questions

Impact of this question