Show how an aldohexose can be used to synthesize 2-ketohexose.
Since glucose is converted to fructose by this method, what can you say about the configuration of `C^(3), C^(4)" and "C^(5)` in the sugars.

Explanation

To synthesize a 2-ketohexose from an aldohexose, we can use glucose (an aldohexose) as our starting material. The process involves a series of steps that convert the aldehyde group of glucose into a ketone group, resulting in fructose (a 2-ketohexose). Here’s how the synthesis can be outlined step by step:

### Step 1: Structure of Glucose
First, we need to recognize the structure of glucose, which is an aldohexose. The structure can be represented as follows:

- **Glucose Structure**:
- CHO (aldehyde group)
- C1: CH2OH
...