See image — Hydrocarbons Chemistry Question

💡 Solution & Explanation

Step 1: Identify the starting material. The starting material is cyclooctene bearing a -CH2OH (hydroxymethyl) substituent on one of the double-bond carbons. Cyclooctene is an 8-membered ring with one double bond. Step 2: Ozonolysis with H2O2 (oxidative workup). Ozonolysis of the cyclooctene double bond with oxidative workup (O3 then H2O2) cleaves the double bond and oxidizes both aldehyde intermediates to carboxylic acids. This opens the 8-membered ring and gives a linear dicarboxylic acid (or hydroxy diacid). One carbon of the double bond bears the -CH2OH group, so after cleavage we get a linear chain with -CO2H at one end, then the carbon bearing -CH2OH, and continuing to another -CO2H at the other end. The 8-membered ring (8 carbons) opened at the double bond gives an 8-carbon chain: HO2C-CH(CH2OH)-(CH2)5-CO2H. This is compound (A): 2-(hydroxymethyl)octanedioic acid (a hydroxy diacid). Step 3: Dehydration with heat (-H2O, Delta). Compound (A) contains a -CH2OH group on C2 and a -CO2H at C1. The hydroxymethyl group (-CH2OH) can attack one of the carboxylic acid groups intramolecularly to form a lactone. The -CH2OH oxygen attacks the nearby C1 carboxyl to form a 5-membered gamma-lactone (butyrolactone), releasing water. This forms a gamma-butyrolactone (5-membered ring: O-CH2-CH-C(=O)-O in ring) where the ring carbon bears the pendant -(CH2)5-CO2H chain. Step 4: Structure of product (B). The lactone ring is 5-membered with -CH2- (from the original CH2OH) as part of the ring, a ring CH bearing the -(CH2)5-CO2H chain, and the carbonyl. This matches option (b): a 5-membered lactone with -CH2OH incorporated into the ring oxygen side, and a -(CH2)5-CO2H chain on the alpha carbon to the carbonyl. Step 5: Why other options fail. - Option (a): Shows HO- directly on the ring carbon (not -CH2- bridging), incorrect regiochemistry. - Option (c): Shows -(CH2)4-CO2H chain, which would require a 7-membered ring starting material, not cyclooctene (8-membered ring gives 6 CH2 groups in the chain, consistent with (CH2)5). - Option (d): Shows a 6-membered lactone (delta-lactone), which would form if the -CH2OH attacked the distal carboxyl, but the proximal 5-membered lactone is strongly favored kinetically and thermodynamically. Therefore, the correct answer is B.