Does Tautomerization Regenerate Phenylethanone in NaH Reaction?

[Natalie456]

The instructions only specified that phenylethanone would react with NaH followed by an acid quench. I know that NaH provides a hydride (H-), and this will "take" one of the hydrogens on the exposed methyl group.

I followed this by pushing electrons so that the negative charge was on the oxygen, rather than carbon, and the acid quench (H+) would form an enol. However, doesn't tautomerization to a ketone product just regenerate phenylethanone again, or am I missing something? Thank you for your time. No amounts for any reagent were specified.

 

[TeethWhitener]

What happens if, instead of thinking of H^- as a base, you think of it as a nucleophile?

 

[epenguin]

The instructions only specified that phenylethanone would react with NaH followed by an acid quench. I know that NaH provides a hydride (H-), and this will "take" one of the hydrogens on the exposed methyl group.

I followed this by pushing electrons so that the negative charge was on the oxygen, rather than carbon, and the acid quench (H+) would form an enol. However, doesn't tautomerization to a ketone product just regenerate phenylethanone again, or am I missing something? Thank you for your time.No amounts for any reagent were specified.

Does it? I’m rusty but I thought the H^- went to the carbonyl C*, after which you can’t make that tautomerism work. Is NaH qualitatively different from other reducing agents?
Can you write out a scheme?

*Often pictured as δ+ due to electron withdrawal onto the more electronegative O pictured =O δ-.