In the first problem,think like this,
You have 3 carbon atoms in the first molecule 6 in the second.
Now think of a way to connect those 2 carbon chains together.
Can you see that one of the chains marked red in the second molecule appears like that of a aldehyde/ketone. Now you should think that your conversion must have an intermediate aldehyde/ketone.
So you can do it in two different ways.
In the second problem,take it like this,
Here you have 4 left side and 9 right side. Now you have to add an extra carbon to the chain.
To add an extra carbon you can,
- use CO2with grignard
- use HCHO with grignard
But if you are give only to use 1- butene only as an organic compound , you have to use CO
2 as it is considered as an inorganic compound.
You can do this conversion with the skill you get from the first problem.
Do it yourself and show what you have tried.