Identify the major product formed in the following reaction:

Step-by-step solution

The given reaction is a Robinson annulation, which involves a Michael addition followed by an intramolecular aldol condensation. The base abstracts the acidic -proton from isobutyraldehyde to form an enolate ion. (CH₃)₂CH-CHO + CH₃O⁻ (CH₃)₂C⁻-CHO + CH₃OH The enolate acts as a Michael donor and attacks the -carbon of methyl vinyl ketone. (CH₃)₂C⁻-CHO + CH₂=CH-CO-CH₃ OHC-C(CH₃)₂-CH₂-CH₂-CO-CH₃ This intermediate is 2,2-dimethyl-5-oxohexanal. An intramolecular aldol condensation then occurs. The base abstracts an -prot