Here are two compounds:

Compound H:

enter image description here

and compound I:

enter image description here

Compound H reactions with the reagent shown below to form compound I and two other products.

How would you clarify this reaction? I thought it was a reduction, because we are losing the oxygen bonded on the left hand side of the molecule. The actual answer is elimination Any advice for tell-tale signs for this type of reaction, and why my answer was wrong?

enter image description here

  • 1
    $\begingroup$ The oxygen-bonded group isn't the only thing you're losing. I assume you know what these structures mean -- draw in all the hydrogens explicitly (OK, skip those on the ring) and count them carefully. $\endgroup$ Jan 10, 2021 at 18:31
  • 1
    $\begingroup$ If the phosphate group were a bromine, would you even ask the question? $\endgroup$
    – user55119
    Jan 10, 2021 at 18:43
  • $\begingroup$ @orthocresol - I'm not sure what you're getting at, unfortunately, I counted the Hs up but how does that help? What tells you that this is an elimination reaction? $\endgroup$
    – vgupt
    Jan 11, 2021 at 11:50
  • $\begingroup$ You're losing an oxygen-based group (the phosphate), yes, but you're also losing a hydrogen. $\endgroup$ Jan 11, 2021 at 12:26
  • 1
    $\begingroup$ By the way - this isn't a criticism of you, but rather I feel I should point it out, as you seem to be taught otherwise - "oxidation/reduction" and "addition/elimination" are entirely orthogonal concepts to one another. An elimination reaction can be oxidative, reductive, or indeed redox-neutral. The reaction you have here falls into this last category: it is an elimination (you are losing groups across a double bond), but there is no redox going on, as the overall oxidation state is preserved. $\endgroup$ Jan 11, 2021 at 12:31


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