Question

Question:The cis and trans isomers of 2-butene give different cyclopropane productsin the Simmons–Smith reaction. Show the structures of both, and

explain the difference.

Short answer

Answer

Structures of the reaction products are:

Step-by-step solution

Simmons- Smith reaction

Simmons- Smith’s reaction was given by Howard Ensign Simmons, Jr. and Ronald D. Smith. Reagent Diiodomethane in the presence of zinc-copper complex will form methylene free radical, and it will react with double bonds of alkene and form a cyclopropane ring.

Explanation

In Simmons- smith reaction, alkene will act as a nucleophile and form a cyclopropane ring, and a cyclopropane ring will form on the less hindered side of the compound.

Geometry of product

The cis isomer of 2- butene will form cis product, and trans-2- butane will form trans-1,2-dimethylcyclopropane. Therefore, we can say that the Simmons- smith reaction will do syn- addition. Hence, the product of reactions are: