Question

Which of the following is/are conditions for $S_{N}NGP$ reaction to occur?

• A. Nucleophile should be present within the molecule/internally.
• B. Generally, nucleophile and leaving group should be present anti to each other at 1,2 position.
  
• C. Nucleophile and leaving group should be present syn to each other
• D. Concentration of nucleophile (external) should be less

Answer 1

Answer: (A), (B), (D)

Concentration of nucleophile (external) should be less

Conditions of $S_{N}NGP$ reaction mechanism:

Nucleophile should be a part of the reacting molecule to undergo intramolecular reaction. It attacks the leaving group intramolecularly.

Generally, nucleophile and leaving group should be present anti to each other at 1,2 position so that the nucleophile will attack the leaving group from the back.

Concentration of external nucleophile should be less otherwise it promotes the $S_{N}2$ reaction mechanism.