Identify the major product formed in the following reaction sequence.

Step-by-step solution

The given starting material is cyclopentanecarboxylic acid, which contains a highly acidic carboxylic proton ( -COOH ). Grignard reagents (like EtMgBr ) are strong bases as well as strong nucleophiles. However, acid-base reactions are much faster than nucleophilic addition reactions. When 1 equivalent of EtMgBr is added, it acts as a base and abstracts the acidic proton from the carboxylic acid to form a carboxylate salt and ethane gas: Cyclopentyl-COOH + EtMgBr Cyclopentyl-COO ^-MgBr^+ + Et-H Since only 1 equivale