Draw the structures of organic compounds a and b omit all by products thf

The reaction is shown below,

Step 1: Hydration of Alkene:

In first step Ethene is hydrated to Ethanol through Hydroboration Reaction.

Step 2: Oxidation of Primary Alcohol:

In this step partial oxidation of ethanol is carried out using mild Oxidizing agent Pyridinium chlorochromate (PCC) and Acetaldehyde is produced.

Step 3: Reduction of Acetaldehyde followed by Oxidation:

In this step, first acetaldehyde is reduced to secondary alcohol using grignard reagent. After that the sec. alcohol is oxidized to ketone by using oxidizing agent CrO ₃.