JEE Advanced levelSingle correct optionDifficulty 3 of 3nc180
Assertion: Hofmann bromamide degradation of an optically active amide R−CONHX2 in which R is chiral at the carbon attached to C=O gives an amine of retained configuration.
Reason: The R group migrates from carbon to nitrogen with inversion of configuration while forming the isocyanate.
ABoth Assertion and Reason are true and the Reason is the correct explanation of the Assertion
BAssertion is true but Reason is false
CAssertion is false but Reason is true
DBoth Assertion and Reason are true but the Reason is not the correct explanation of the Assertion
Answer: B
The migrating group moves with its bonding electrons to the electron-deficient nitrogen in a concerted step and keeps its configuration (retention). The Assertion is therefore true and the Reason, which claims inversion, is false.