The reaction of `(S)-2` methybutanamide with `Br_(2)` and `Ohbar` produces on optically active amine The product is .

Options

A. Rsec-butylamine
B. (S)-sec-butylamine
C. `(+-)` sec- butylamine
D. (R )-iso butylamine

Answer

B

Explanation

`underset((S)-2-"Methylbutanamide (S)-sec-Butylamine")(CH_(3)CH_(2)underset(CH_(3))underset(|)(C)H-overset(O)overset("||")(C)-NH_(2)overset(Br_(2))underset(OH^(-))rarrCH_(3)CH_(2)underset(CH_(3))underset(|)(CH)HNH_(2))`
The product is `(S)` sec-butylamine The alky1 group ` ( :R)` migrates with its electron pair to the electron-deficient `N` and configuration is retained because `C-C` bond is being broken at the same time that `C-N` bond is being formed in the transition state.