Question

Using your reaction roadmap as a guide, show how to convert butane into 2-butanone. Show all reagents and all molecules synthesized along the way.

Short answer

Question: Outline the process of converting butane into 2-butanone using a reaction roadmap. Answer: The conversion of butane into 2-butanone can be achieved in the following steps: 1. Formation of 1-bromobutane through a substitution reaction with bromine (Br2) in the presence of UV light. 2. Formation of 2-pentanone via a Grignard reaction by reacting 1-bromobutane with magnesium metal in dry ether to form Butylmagnesium bromide, followed by a reaction with ethanal (CH3CHO). 3. Reduction of the carbonyl group in 2-pentanone to form 2-pentanol using sodium borohydride (NaBH4). 4. Dehydration of 2-pentanol to form 2-butene using sulfuric acid (H2SO4) in an E1 reaction. 5. Oxymercuration-demercuration reaction to convert 2-butene into 2-butanone using Mercuric acetate (Hg(OAc)2), water (H2O) in Tetrahydrofuran (THF), and sodium borohydride (NaBH4).

Step-by-step solution

Formation of 1-bromobutane

First, we will convert butane into 1-bromobutane via a substitution reaction. To achieve this, react butane with bromine (Br2) in the presence of UV light. The UV light will cause homolytic cleavage of the bromine molecule, creating free radicals that can react with the butane to produce 1-bromobutane. The reaction can be represented as: Butane + Br2 (UV light) -> 1-bromobutane

Formation of 2-pentanone (Grignard reaction)

Next, we need to introduce an additional carbon to the molecule and a carbonyl group. This can be accomplished through a Grignard reaction. First, react the 1-bromobutane with magnesium metal in dry ether to produce the corresponding Grignard reagent (Butylmagnesium bromide): 1-Bromobutane + Mg (dry ether) -> C4H9MgBr (Butylmagnesium bromide) Then, react the Butylmagnesium bromide with a suitable carbonyl compound, like ethanal (CH3CHO). This reaction will add a carbonyl group and an additional carbon from ethanal: C4H9MgBr + CH3CHO -> 2-Pentanone + Mg(OH)Br

Reduction of 2-pentanone to 2-pentanol

Now, we will reduce the carbonyl group in 2-pentanone to an alcohol by reacting with sodium borohydride (NaBH4). This step will produce 2-pentanol: 2-Pentanone + NaBH4 -> 2-Pentanol + NaB(OH)3

Dehydration of 2-pentanol to 2-butene

In this step, we will convert 2-pentanol into 2-butene via an E1 dehydration reaction using an acid like sulfuric acid (H2SO4): 2-Pentanol + H2SO4 -> 2-Butene + H2O

Oxymercuration-demercuration of 2-butene to form 2-butanone

Finally, we will perform an oxymercuration-demercuration reaction to convert the 2-butene into 2-butanone. First, react 2-butene with Mercuric acetate (Hg(OAc)2) and water (H2O) in Tetrahydrofuran (THF): 2-butene + Hg(OAc)2 (THF) + H2O -> [(Hg(OAc)2)2-Butanol] (Mercury complex) Next, react the mercury complex with sodium borohydride (NaBH4) to remove the mercury and form the final product, 2-butanone: [(Hg(OAc)2)2-Butanol] + NaBH4 -> 2-Butanone + Hg + products of NaBH4 With these steps, we converted butane into 2-butanone using various reagents and reactions according to the reaction roadmap.