The major product formed in the following reaction is

Explanation:-

• The reaction pathway is shown below:

• In the first step of the reaction, it is shown that the reaction of Ac₂O with Lewis acid BF₃ forms a carbocation (CH₃CO⁺) which reacts to form an intermediate product.

• In the next step of the reaction, the intermediate product undergoes a cyclization reaction through the release of a molecule of H₂O followed by a [4+2] cycloaddition and decarboxylation reaction to give the final product.

Conclusion:-

Hence, the major product formed in the following reaction is