Organic Chemistry Substitution Reaction
Predict the major products for the reaction and show the full mechanism
![](/old/images/sn1.gif)
![](/24/organic-chemistry-substititution-problem.png)
An SN2 reaction, which stands for substitution, nucleophilic, bimolecular, is a fundamental mechanism in organic chemistry. The term "bimolecular" indicates that the rate-determining step involves two reactant molecules: the nucleophile and the alkyl halide. The defining characteristic of the SN2 mechanism is its single-step process without any intermediates. During this reaction, the nucleophile attacks the alkyl halide (or tosylate) from the side opposite the leaving group. As the nucleophile forms a bond with the carbon atom, the leaving group simultaneously departs from the other side. This concerted mechanism results in the inversion of the stereochemical configuration of the substrate.
![](/24/sn2-mechanism.png)
The mechanism of the SN2 reaction. The reaction takes place in a single step when the incoming nucleophile approaches from a direction 180° away from the leaving halide ion, thereby inverting the stereochemistry at carbon.
1. The nucleophile -OH uses its lone-pair electrons to attack the alkyl halide carbon 180 degrees away from the departing halogen. This leads to a transition state with a partially formed C-OH bond and a partially broken C-Br bond.
2. The stereochemistry at carbon is inverted as the C-OH bond forms fully and the bromide ion departs with the electron pair from the former C-Br bond.
Related Problems
Predict the major products for the reaction and show the full mechanism
![](/old/images/sn2.gif)
Predict the major products for the reaction and show the full mechanism
![](/old/images/nucleophilic-substitution.gif)
Predict the major products for the reaction and show the full mechanism
![](/old/images/sn2-mechanism.gif)