MolSynapsequestion bank
MolSynapse / Question bank / Haloalkanes and Haloarenes / Stereochemical outcomes of substitution
JEE Advanced levelOne or more correct optionsDifficulty 3 of 3hx217

(R)-Butan-2-ol is converted into 2-halobutanes by the following methods. Select the correct statements about the main product.

  1. A gives (R)-2-bromobutane.
  2. B with pyridine gives (R)-2-chlorobutane.
  3. C/pyridine, then in dry acetone, gives (S)-2-bromobutane.
  4. D without base gives (R)-2-chlorobutane.

Answer: C, D

SOCl2 alone gives retention (R). With pyridine, backside attack gives inversion (S). TsCl forms the tosylate with retention at carbon; bromide then displaces by SN2 with inversion to give (S)-2-bromobutane. PBr3 acts by SN2 and also gives (S).
Practice Haloalkanes and Haloarenes More on Stereochemical outcomes of substitution
Previous questionNext question

More questions on Stereochemical outcomes of substitution