When $\ce{RMgX}$ (Grignard reagent) reacts with chloramine ($\ce{NH2Cl}$) it forms $\ce{RNH2}$.

But why doesn't it form $\ce{RH}$ by taking a hydrogen atom from chloramine as the negative charge so developed on nitrogen will be more stable as nitrogen has high electronegativity and $\ce{Cl}$ being a electron withdrawing group further stabilise the anion.

So where am I wrong? Can anybody suggest a mechanism?

  • $\begingroup$ On nitrogen, chlorine is no longer electron-withdrawing. In $\ce{NCl3}$, chlorine actually bears the partial positive charge (demonstrated by reacting with chloride ions to form chlorine gas). $\endgroup$ – Jan Nov 19 '17 at 14:05
  • $\begingroup$ Still may be more electron wothdrawing/less electron releasing than hydrogen, though. $\endgroup$ – Oscar Lanzi Nov 19 '17 at 20:53

The $\ce{N-H}$ protons are relatively weakly acidic and this makes deprotonation kinetically less favored if an alternative nucleophilic attack mechanism is available. With $\ce{NH3}$ no such alternative is there, due to lack of a decent leaving group, so deprotonation ultimately prevails; but $\ce{NH2Cl}$ allows displacement of a chloride ion and thus enables nucleophilic attack.


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