Question

Using your roadmaps as a guide, show how to convert cyclohexane into adipoyl dichloride. Show all reagents and all molecules synthesized along the way.

Short answer

Question: Outline the key steps and reagents needed to convert cyclohexane into adipoyl dichloride. Answer: To convert cyclohexane into adipoyl dichloride, the following steps and reagents are required: 1. Formation of cyclohexene by dehydrogenation using a Pd or Pt catalyst. 2. Formation of 1,4-cyclohexadiene through bromination using Br2 and CCl4, followed by dehydrohalogenation using t-BuOK. 3. Ring opening using ozone (O3) and reduction with zinc (Zn) and acetic acid (HOAc) to form hexanedial. 4. Formation of hexane-1,6-diamine by reductive amination using ammonia (NH3) and sodium cyanoborohydride (NaBH3CN). 5. Formation of adipoyl dichloride by reacting the product with thionyl chloride (SOCl2).

Step-by-step solution

Formation of Cyclohexene by Dehydrogenation of Cyclohexane

To form a diene from cyclohexane, first, we need to dehydrate cyclohexane to cyclohexene. The reagent needed for this transformation is palladium (Pd) or platinum (Pt) catalyst. The reaction proceeds as follows: Cyclohexane → Cyclohexene using Pd or Pt catalyst.

Formation of 1,4-Cyclohexadiene by Bromination and Dehydrohalogenation

Next, bromination of cyclohexene will be carried out using molecular bromine (Br2) in the presence of a non-polar solvent like CCl4. Then, dehydrohalogenation is carried out using a strong base like tert-butoxide (t-BuO-) to form 1,4-cyclohexadiene. The reactions can be written as: Cyclohexene + Br2 → 3,4-dibromocyclohexene using CCl4 as solvent; 3,4-dibromocyclohexene + 2 t-BuOK → 1,4-cyclohexadiene + 2 KBr + 2 t-BuOH.

Ring Opening using Ozone and Reduction with Zinc

The next step would be to open up the 6-membered ring of the 1,4-cyclohexadiene. The ring-opening reagent used for this step is ozone (O3) followed by a reducing agent – zinc (Zn) and acetic acid (HOAc). This results in the formation of hexanedial. The reaction can be represented as: 1,4-cyclohexadiene + O3 → Hexane-1,6-dione + Zn/HOAc (Ozonolysis, followed by reduction).

Formation of Hexane-1,6-diamine by Reductive Amination

Now, the goal is to convert the hexane-1,6-dione formed in the previous step to hexane-1,6-diamine. This can be achieved through reductive amination using ammonia (NH3) and a strong reducing agent like sodium cyanoborohydride (NaBH3CN). The reaction can be written as: Hexane-1,6-dione + 2 NH3 + 2 NaBH3CN → Hexane-1,6-diamine.

Formation of Adipoyl Dichloride by Reaction with Thionyl Chloride

Finally, to convert the hexane-1,6-diamine to adipoyl dichloride, we will use thionyl chloride (SOCl2). The reaction proceeds by replacing the two amine groups with chloride atoms. The resultant product will be adipoyl dichloride along with the formation of side products such as HCl and SO2. The reaction can be written as: Hexane-1,6-diamine + 2 SOCl2 → Adipoyl Dichloride + 2 HCl + 2 SO2. Now, all the intermediates and reagents have been shown, and the conversion of cyclohexane to adipoyl dichloride has been accomplished through a series of chemical reactions.