The major product formed in the following reaction is

Concept:-

• The Aldar-ene reaction or ene reaction is a chemical reaction that involves an alkene with an allylic hydrogen (ene reaction) and enophile (a compound containing a multiple bond) to form a new σ-bond with the migration of the ene double bond and 1,5 hydrogen shift. 
• The mechanism of the following reaction is given below:

Explanation:-

• The mechanism of the reaction is shown below:

• From the above reaction, we can see that in the first step of the reaction Ti(OⁱPr)₄ acts as a lewis acid and forms complex with the oxygen atom of the more electrophilic aldehyde functional group of the substrate.
• In the next step, the complex undergoes an ene reaction with the diene.

Conclusion:-

Hence, the major product formed in the following reaction is