The best method for the preparation of 2,2-dimethylbutane is via the reaction of

Options

A. `Me_3CBr` and `MeCH_2Br` in Na/ether
B. `(Me_3C)_2 CuLi` and `MeCH_2Br`
C. `(MeCH_2)_2` CuLi and `Me_3CBr`
D. `Me_3CMgI` and `MeCH_2I`

Explanation

To prepare 2,2-dimethylbutane, we can use the reaction of 2-bromo-2-methylbutane with a strong nucleophile. Here’s a step-by-step solution:

### Step 1: Identify the reactants
We need to start with 2-bromo-2-methylbutane (C5H11Br) as our starting material. This compound contains a bromine atom that can be replaced in a nucleophilic substitution reaction.

### Step 2: Choose a strong nucleophile
A suitable strong nucleophile for this reaction is lithium diorganocopper (LiR2Cu), where R is a methyl group (CH3). This will help in the substitution reaction.

### Step 3: Set up the reaction
The reaction can be set up as follows:
\[ \text{2-bromo-2-methylbutane} + \text{Li(CH3)2Cu} \rightarrow \text{2,2-dimethylbutane} + \text{LiBr} \]

### Step 4: Reaction Mechanism
In this reaction, the nucleophile (Li(CH3)2Cu) will attack the carbon atom bonded to the bromine in 2-bromo-2-methylbutane. The bromine will leave, and a new carbon-carbon bond will form, resulting in the formation of 2,2-dimethylbutane.

### Step 5: Product formation
The final product of this reaction is 2,2-dimethylbutane (C5H12), which is a branched alkane.

### Conclusion
Thus, the best method for the preparation of 2,2-dimethylbutane is via the reaction of 2-bromo-2-methylbutane with lithium diorganocopper (Li(CH3)2Cu).

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