What starting material is needed to synthesize each compound by a ring-closing metathesis reaction?

a.

b.

c.

Olefin metathesis proceeds with a complex mechanism. Several metal-carbene intermediates are engaged in metathesis reactions.

Ring formation occurs in certain metathesis reactions, and such reactions are termed ring-closing metathesis reactions.

To identify the starting material to synthesize the given compounds, the C=C bond is cleaved, and CH₂ is incorporated into both the carbons using the double bond.

a. The starting material that is required to synthesize compound a is hepta-1,6-dien-3-one. The structure of the starting material of compound a can be given as follows.

Starting material required to synthesize compound a

b. The starting material that is required to synthesize compound b is 2,3-diallyl-6-methoxycyclohexanol. The structure of the starting material of compound b can be given as follows.

Starting material required to synthesize compound b

c. The starting material of compound c is the carbon chain possessing two terminal carbon alkenes. The starting material of compound c can be given as follows.

Starting material required to synthesize compound c