In a nucleophilic substitution reaction: R - Br + Cl- xrightarrowDMF R - Cl + Br- which one of the following undergoes complete inversion of configuration?

Question

In a nucleophilic substitution reaction: R - Br + Cl- xrightarrowDMF R - Cl + Br- which one of the following undergoes complete inversion of configuration? (A) C6H5CHC6H5Br (B) C6H5CH2Br (C) C6H5CH(CH)3Br (D) C6H5CCH3C6H5Br

Tardigrade Admin · Accepted Answer

In the compound of option B, bromine is attached to a primary carbon atom. The substitution occurs via SN 2 mechanism which involves the inversion of configuration. In the remaining compounds the bromine is attached to a secondary or tertiary carbon atom. In case of secondary carbon atom (options A and C), the substitution occurs via a combination of S N 1 and S N 2 mechanisms. Hence, complete inversion of configuration is not possible. In case of tertiary carbon atom, (option D) the substitution occurs via SN 1 mechanism which cannot result in complete inversion of configuration.

Q. In a nucleophilic substitution reaction:
$R - B r + C l^{-} D MF R - Cl + B r^{-}$
which one of the following undergoes complete inversion of configuration?

$C_{6} H_{5} C H C_{6} H_{5} B r$

$C_{6} H_{5} C H_{2} B r$

$C_{6} H_{5} C H (C H)_{3} B r$

$C_{6} H_{5} CC H_{3} C_{6} H_{5} B r$

Q. In a nucleophilic substitution reaction: R−Br+Cl−DMF​R−Cl+Br− which one of the following undergoes complete inversion of configuration?

C6​H5​CHC6​H5​Br

C6​H5​CH2​Br

C6​H5​CH(CH)3​Br

C6​H5​CCH3​C6​H5​Br

Q. In a nucleophilic substitution reaction:
$R - B r + C l^{-} D MF R - Cl + B r^{-}$
which one of the following undergoes complete inversion of configuration?

$C_{6} H_{5} C H C_{6} H_{5} B r$

$C_{6} H_{5} C H_{2} B r$

$C_{6} H_{5} C H (C H)_{3} B r$

$C_{6} H_{5} CC H_{3} C_{6} H_{5} B r$