Q 11-11-34 E - Organic Chemistry (Mcmurry)

Question

Reaction of iodoethane with  yields a small amount of isonitrile,${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{N}\equiv \mathrm{C}$, along with the nitrile ${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{C}\equiv \mathrm{N}$ as the major product. Write electron-dot structures for both products, assign formal charges as necessary, and propose mechanisms to account for their formation.

Step-by-Step Solution

Answer

The mechanism for the reaction and the structure of arginine is,

Electron-dot structure

Electron-dot structures are the Lewis structures that show the valence electrons around an atom as a dot. A single bond represents one dot pair and a double bond for two dot pairs.

The electron-dot structures for both the products with assigned formal charges and their mechanism

There is an S_N2 attack by the lone pairs on carbon, which gives the nitrile product, and an attack by the lone pair electrons on nitrogen, which gives the isonitrile product.

                  Assigning formal charges and their mechanism