Q11-2P - Organic Chemistry (Mcmurry)

Question

What product would you expect to obtain from ${\mathbf{S}}_N\mathbf{2}$ reaction of  ${\mathbf{OH}}^{-}$with (R)-2-bromobutane? Show the stereochemistry of both the reactant and product.

Step-by-Step Solution

Answer

                   

                           (R)-2-bromobutane                              (S)-2-butanol

Step-by-step Solution Step 1: Nucleophilic bimolecular substitution reaction S N 2

The ${\mathrm{S}}_{\mathrm{N}}2$ reaction is a nucleophilic substitution reaction where bond is broken and other is form simultaneously. Two reacting species involved in the rate determining step of the reaction. The term ${\mathrm{S}}_{\mathrm{N}}2$ stands for substitution nucleophilic bimolecular.

                                                            ${\mathrm{S}}_{\mathrm{N}}2$ Reaction

Step 2: Inversion of configuration

Inversion of configuration is a process in which the configuration of an atom is changed. If the atom in a question is a stereocenter, inversion of configuration usually changes R absolute configuration in to S, and S into R. Inversion of configuration can also convert cis into trans, or trans into cis.

Step 3: Show the stereochemistry of both the reactant and product

By identifying the leaving group and chirality center,draw the product carbon skeleton, inverting the configuration at the chirality center, and replace the leaving group (bromide) with the nucleophilic reactant (OH^-).Formation of product of the reactant with its Stereochemistry is shown below:

                              

                                  (R)-2-bromobutane                              (S)-2-butanol