Anodic oxidation brings back some good memories

Here is an interesting electrocatalytic aziridination reaction just published by Dan Little of UCSB ( Reading this work was akin to a flashback, at least for me. My lab developed very similar chemistry about 13 years ago ( Our postulated mechanism was different, though, and I still think we were correct because we were able to show that iodosobenzene derivatives oxidized N-aminophthalimide in a similar manner to our anodic process. I have always liked the analogy between the hydroxylamine intermediate and mCPBA. Atkinson used to run these sorts of processes way before any of us, although he used super-stoichiometric amounts of lead tetraacetate, which is one nasty reagent. In his Org. Lett. paper, Dan postulates a radical mechanism and it very well may be operating in the present reincarnation of the nitrene transfer. I was really surprised to see that both cis and trans alkenes lead to the cis-aziridine isomer. Ordinarily, cis-epoxides and aziridines are less stable than their trans-counterparts, but N-aminophthalimide substituent is special… These peculiarities aside, it is too bad that N-aminophthalimide is more or less the only amine that reliably participates in these kinds of reactions. Why? There are many reasons, but the most obvious one is this: the amino terminus of N-aminophthalimide is fairly nucleophilic, yet sterically unencumbered. In addition, there are no hydrogens at the alpha position. Taken together, these features lead to oxidation reactions that are relatively free of by-products.


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