We do know that the Grignard Reagent is $\ce{RMgX}$ where R is some alkyl group & X is any halogen group. So, my question is that, whether $\ce{HMgX}$ is also a Grignard Reagent like $\ce{RMgBr}$?


According to this reference $\ce{HMgX}$ compounds are a thing. You can't make them with magnesium +$\ce{HX}$, of course (what actually happens?), but you can get them from magnesium halide salts plus an "active" form of magnesium hydride in THF. They act as hydride ion sources for reaction with $\ce{AlH3}$ and $\ce{BH3}$ (forming mixed tetrahydridoaluminate and tetrahydridoborate salts, respectively), so we may reasonably expect the same sort of hydride transfer with organic substrates. Such a hydride transfer would be analogous to conventional Grignard reagents transferring their alkyl or aryl anion moieties.

  • 4
    $\begingroup$ But it is probably better not to call them a Grignard reagent as they will have far more in common with metal hydrides. $\endgroup$
    – matt_black
    Dec 8 '18 at 15:39
  • $\begingroup$ Do we call them "Grignard reagents"? Do we call Pluto or Ceres a "planet"? That's ultimately not so much a law of nature as our nature. $\endgroup$ Dec 9 '18 at 22:48

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.