Which of the following structures represents the major product formed by the self-aldol condensation of pentan-3-one?

Step-by-step solution

The reaction is the self-aldol condensation of pentan-3-one, CH₃CH₂COCH₂CH₃ . First, a base removes an -proton from pentan-3-one to form a nucleophilic enolate. CH₃CH₂COCH₂CH₃ OH^- CH₃CH₂COC^-HCH₃ + H₂O The enolate then attacks the electrophilic carbonyl carbon of another pentan-3-one molecule. CH₃CH₂COCH₂CH₃ + CH₃CH₂COC^-HCH₃ CH₃CH₂C(O^-)(CH₂CH₃)CH(CH₃)COCH₂CH₃ The intermediate alkoxide is protonated to form an aldol ( -hydroxy ketone), which subsequently undergoes dehydration upon heating to form an , -unsaturate