The burden of oxidation

We have been moving to a new house over the past few days and now that it is over, I want to talk about my action-packed trip to Florida State University last week. Professor Igor Alabugin (http://www.chem.fsu.edu/~alabugin/) invited me to Tallahassee, where I gave two talks. One of these lectures was for a general audience, while and the other was more specialized for the organic folks. Igor has been keeping a vibrant research program. I had a chance to attend Igor’s group meeting and met some of his students over lunch. I want to draw your attention to the book on stereoelectronic effects he recently published. A previous book dedicated to this enduring concept dates back to Pierre Deslongchamps’s herculean effort. Upon my return, I ordered Igor’s contribution from amazon.com and I recommend that you take a look at it as well (https://www.amazon.com/Stereoelectronic-Effects-Between-Structure-Reactivity/dp/1118906349). The coverage of the field is outstanding and I am really glad that there is no need to have hard copies anymore. Go iBooks, baby!

During my trip down south I also had a chance to meet Jim Frederich (http://www.frederichlab.org), an assistant professor at FSU. Jim has established an active research program in chemical synthesis. Below is a link to his first paper, which I think is outstanding, particularly for someone like me who, in his spare time, loves to keep track of oxidation states. The manuscript documents a photochemical conversion of pyridazine N-oxides into pyrazoles. Pyrazoles are typically derived from 1,3-dicarbonyl compounds in a transformation that does not require oxidation state adjustment. The pyridazine starting materials used by Jim have their nitrogen atoms at a higher oxidation state compared to pyrazole. Superficially, the transformation of an N-oxide into a pyrazole raises an eyebrow or two, but only if you forget that the product’s ketone functionality shifts “the redox burden” outside the ring. I encourage you to think of a reasonable mechanism (one of these days, I might use this reaction in my cume).

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http://pubs.acs.org/doi/abs/10.1021/acs.orglett.6b02562

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