Reaction shown

How does the mechanism of this reaction with BzONHMe work? Can part of it act as a base and abstract the alpha proton? Would be great if someone could help me!

  • $\begingroup$ This can't act as a base. It is a hydrochloride salt. $\endgroup$ – Zhe Mar 12 '17 at 17:21

The first step is the formation of the Me,O-Bz imine of the ketone. This tautomerises to the enamine which then does a pericyclic rearrangement with the carbonyl of the benzoyl group to install O at the alpha position. Finally the imine hydrolyses to reveal the ketone. See Aldrich Chemfiles (2007) 7.1, page 7.

Abridged mechanism

  • $\begingroup$ So the HCl doesn't really do anything? Can't it protonate the ketone and then the alpha-proton gets abstracted by the amine resulting in a positive charge on the amine, letting the neighbouring oxygen get taken by the double bond between carbonyl carbon and alpha-carbon? $\endgroup$ – ClaraMarie Mar 13 '17 at 18:09
  • $\begingroup$ Remember that the substrate you are reacting with has a basic centre which is more basic than the benzoylhydroxylamine $\endgroup$ – Waylander Mar 13 '17 at 18:42
  • $\begingroup$ Thank you very much! I figured it out now, your mechanism makes a lot of sense! $\endgroup$ – ClaraMarie Mar 13 '17 at 22:21
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    $\begingroup$ @ClaraMarie If an answer has helped you, it's a good idea to upvote and/or accept it (green tick next to voting buttons). Please read What should I do when someone answers my question? for further details. $\endgroup$ – orthocresol Mar 26 '17 at 19:17

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