Diethyl propanedioate is treated with (i) NaOEt, then CH3CH2Br; (ii) NaOEt, then CH3I; (iii) aqueous acid with heating. The final organic product is

JEE Advanced levelSingle correct optionDifficulty 3 of 3g3076

Diethyl propanedioate is treated with (i) $NaOEt$ , then $CH X_{3} CH X_{2} Br$ ; (ii) $NaOEt$ , then $CH X_{3} I$ ; (iii) aqueous acid with heating. The final organic product is

Two successive alkylations at the active methylene give

(CH X_{3}) (C X_{2} H X_{5}) C (COOEt) X_{2}

. Acid hydrolysis converts both esters into

- COOH

, and the substituted malonic acid decarboxylates on heating. The product is

CH X_{3} CH X_{2} CH (CH X_{3}) COOH

, 2-methylbutanoic acid.