The major product formed in the following reaction is

Concept:-

This involves Heck coupling followed by Grubb's metathesis.

Heck coupling :

• It is the cross-coupling reaction of an organic halide with an alkene in the presence of a palladium catalyst and a base to form a new substituted alkene.
• In 1972 T.Mizoroki and R.F. Heck discovered this reaction which is also known as the Mizoroki-Heck reaction.
• It goes through four steps 

(i) Oxidative addition of the palladium - oxidation state of Pd changes from Pd(0) to Pd(II).

(ii) Carbo-metalation - In this step, the carbon-Pd bond reacts with the C=C bond.

(iii)  \(\beta\)-hydride elimination

(iv) Reductive elimination - removal of Pd from C-Pd Bond.

Example:-

Grubb's Synthesis:

In the alkene metathesis reaction, two alkenes undergo [2+2] cycloaddition reaction forming a four-membered cyclo-butane ring structure followed by intramolecular rearrangement to create two different alkenes.

Example:

Explanation:-

The mechanism of the reaction is as follows;

The mechanism of the reaction goes as follows

• The first step involves, Oxidative addition of the palladium -where the oxidation state of Pd changes from Pd(0) to Pd(II)  Furthermore Carbo-metalation occurs, In this step, the carbon-Pd bond reacts with the C=C bond which then proceeds through \(\beta\)-hydride elimination and removal of Pd from C-Pd Bond.
• The second step proceeds via alkene metathesis( which is an intermolecular [2+2] cycloaddition reaction) in the presence of Grubbs' 2nd generation catalyst followed by intramolecular [2+2] cycloaddition.

Conclusion:-

Therefore option 1 is correct.