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JEE Main levelSingle correct optionDifficulty 2 of 3co081

But-3-en-2-one, , reacts with diethyl propanedioate in the presence of a catalytic amount of NaOEt (Michael addition). The 1,4-adduct is

  1. Adiethyl 2-(2-oxobutyl)propanedioate
  2. Bdiethyl 2-(3-oxobutyl)propanedioate
  3. Cdiethyl 2-(2-hydroxybut-3-en-2-yl)propanedioate
  4. Ddiethyl 2-(but-3-en-2-ylidene)propanedioate

Answer: B

The malonate carbanion attacks the beta carbon (the terminal ) of the enone. Protonation of the enolate gives . Attack at the carbonyl carbon would be 1,2-addition and gives the hydroxy compound.
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