Chapter 8.3, Problem 5P

Interpretation Introduction

Interpretation:

The product expected with its stereochemistry when cyclopentene reacts with NBS and water.

Concept introduction:

NBS can be used as a source of bromine, as it is stable, easily handled compound that slowly decompose in aqueous dimethylsulphoxide to yield bromine at controlled rate. Bromine from NBS adds on to the double bond to give a cyclic bromonium ion. Water, being a nucleophile, attacks the bromonium ion from the unshielded side to give an intermediate which loses a proton to yield a bromohydrin as the product. The addition occurs with anti stereochemistry resulting in a trans- product.

To give:

The product expected with its stereochemistry when cyclopentene reacts with NBS and water.