See image — IUPAC and Nomenclature Chemistry Question

💡 Solution & Explanation

Step 1 - Identify the structure: The molecule shown is a six-membered cyclohexane ring bearing an exocyclic carbon-carbon double bond (=CH2 replaced by =C<) at one position, which is itself double-bonded to an oxygen (=C=O). This gives the fragment: cyclohexane ring with C1=C=O. Step 2 - Recognize the functional group: The C=C=O unit is a ketene (cumulated diene with oxygen). When the ketene carbon is part of an exocyclic double bond on cyclohexane, the parent is cyclohexylidene (cyclohexylidene = cyclohexane ring with one carbon bearing an exocyclic double bond) attached to methanone (C=O). Step 3 - Apply IUPAC nomenclature: The exocyclic alkene portion is named as 'cyclohexylidene' (cyclohexylidene = cyclohexyl with a double bond from the ring carbon outward). The terminal =C=O is 'methanone' (one carbon ketone/ketene terminus). Together: cyclohexylidenemethanone. Step 4 - Confirm: Cyclohexylidenemethanone is a cyclic ketene where the ring carbon is doubly bonded to the ketene carbon, which is doubly bonded to oxygen (cyclohexane ring C=C=O). This exactly matches the drawn structure. Therefore, the correct answer is cyclohexylidenemethanone.