Question

Using your reaction roadmap as a guide, show how to convert cyclohexane into hexanedial. Show all reagents and all molecules synthesized along the way.

Short answer

Question: Convert cyclohexane into hexanedial, showing all the reagents and intermediate molecules. Answer: Cyclohexane ->[NaNH2]-> Cyclohexene ->[I2, DMSO]-> 1,6-Hexadiene ->[OsO4, NaHSO3]-> 1,2,5,6-Tetrahydroxyhexane ->[KMnO4, NaHSO4]-> Hexanedial.

Step-by-step solution

Opening the cyclohexane ring to form an alkene

To do this, we can use a strong base like sodium amide (NaNH2) to remove a proton, and then use a reagent like iodine (I2) in the presence of a polar aprotic solvent like dimethyl sulfoxide (DMSO) to facilitate the ring opening. The resulting molecule is 1,6-hexadiene. The reaction sequence can be written as: Cyclohexane ->[NaNH2]-> Cyclohexene ->[I2, DMSO]-> 1,6-Hexadiene

Converting the alkene into a diol

To convert the alkene into a diol, we will use osmium tetroxide (OsO4) followed by sodium bisulfite (NaHSO3) as the reducing agent. This will result in syn-dihydroxylation (addition of two hydroxyl groups on the same side of the alkene) and the formation of the molecule 1,2,5,6-tetrahydroxyhexane. The reaction can be written as: 1,6-Hexadiene ->[OsO4, NaHSO3]-> 1,2,5,6-Tetrahydroxyhexane

Oxidizing the diol to form hexanedial

In order to convert the diol into an aldehyde, we will use potassium permanganate (KMnO4) in a mild acidic condition. This will selectively oxidize the primary alcohols (the hydroxyl groups at C1 and C6) to aldehydes, while leaving the secondary alcohols (the hydroxyl groups at C2 and C5) intact. The acidification with sodium bisulfate (NaHSO4) will facilitate the aldehyde formation. The final molecule, hexanedial, is also known as 1,6-diformyl-2,5-dihydroxyhexane. The reaction can be expressed as: 1,2,5,6-Tetrahydroxyhexane ->[KMnO4, NaHSO4]-> 1,6-Diformyl-2,5-dihydroxyhexane (Hexanedial) In summary, the entire sequence of reactions can be represented as: Cyclohexane ->[NaNH2]-> Cyclohexene ->[I2, DMSO]-> 1,6-Hexadiene ->[OsO4, NaHSO3]-> 1,2,5,6-Tetrahydroxyhexane ->[KMnO4, NaHSO4]-> 1,6-Diformyl-2,5-dihydroxyhexane (Hexanedial)