Ethyl benzoate, C6H5-CO-OC2H5, is treated with excess propylmagnesium bromide, CH3CH2CH2MgBr, in dry ether, followed by H3O+. How many carbon atoms are present in the final organic alcohol product (the ethanol by-product is not counted)? (Give the answer as an integer.)

JEE Advanced levelNumerical answerDifficulty 3 of 3o1151

Ethyl benzoate, $C X_{6} H X_{5} - CO - OC X_{2} H X_{5}$ , is treated with excess propylmagnesium bromide, $CH X_{3} CH X_{2} CH X_{2} MgBr$ , in dry ether, followed by $H X_{3} O X^{+}$ . How many carbon atoms are present in the final organic alcohol product (the ethanol by-product is not counted)? (Give the answer as an integer.)

Numerical answer type, tolerance 0.5.

Two propyl groups add to the carbonyl carbon and ethoxide is lost, giving

C X_{6} H X_{5} - C (OH) (CH X_{2} CH X_{2} CH X_{3}) X_{2}

, 4-phenylheptan-4-ol. Carbon count: 6 (ring) + 1 (carbinol carbon) + 3 + 3 = 13.