JEE Advanced levelSingle correct optionDifficulty 3 of 3hc184
Free radical bromination of optically pure (S)-3-methylhexane at the tertiary C-H, with BrX2 and light, gives 3-bromo-3-methylhexane as:
AA single enantiomer with retention of configuration
BA single enantiomer with inversion of configuration
CA racemic mixture
DA meso compound
Answer: C
Abstraction of the tertiary H gives a planar (sp2) tertiary radical. BrX2 attacks either face with equal probability, giving equal amounts of both enantiomers, so the product is racemic and optically inactive.