Determine the best hydride donor [duplicate]








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[Which compound reacts faster in the Cannizzaro Reaction?](/questions/33049/which-compound-reacts-faster-in-the-cannizzaro-reaction)

 (3 answers)
 

Closed 5 years ago.



In the given question, the solution (according to the book) says that the electron withdrawing group will facilitate hydride transfer (not mentioning how so) and therefore, said the answer to be (D). But should not (C) be the answer, as the electron donating $\ce {-OCH3}$ group creates a "pushing" effect?


![enter image description here](https://i.stack.imgur.com/yOOTD.jpg)




I would like to say that you must be knowing that the best hydride donor is almost always the entity with most partial positive charge, which is most in $\bf D$ due to strong electron withdrawing group $\bf \ce{-NO\_2}$ both via inductive and resonance effects,. Remember $\bf\ce{-OCH3}$ in $\bf C$ is actually an electron donating group via resonance and electron withdrawing group via inductive effect of which former dominates largely. I think the rest two are pretty simple.


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