Stereo selective and stereo specific reactions with example

Dear Puneet

Stereoselective is a similar term, but it refers to the preferential formation of a stereoisomer rather than a constitutional isomer. If a reaction that generates a carbon– carbon double bond or an asymmetric carbon in a product forms one stereoisomer preferentially over another, it is a stereoselective reaction. In other words, it selects for a particular stereoisomer. Depending on the degree of preference for a particular stereoisomer, a reaction can be described as being moderately stereoselective, highly stereoselective, or completely stereoselective.

A reaction is stereospecific if the reactant can exist as stereoisomers and each stereoisomeric reactant leads to a different stereoisomeric product or a different set of stereoisomeric products.

In the preceding reaction, stereoisomer A forms stereoisomer B but does not form D, so the reaction is stereoselective in addition to being stereospecific. All stereospecific reactions, therefore, are also stereoselective. All stereoselective reactions are not stereospecific, however, because there are stereoselective reactions in which the reactant does not have a carbon–carbon double bond or an asymmetric carbon, so it cannot exist as stereoisomers.

Regards

Arun (askIITians forum expert)