Kornblum oxidation

The Kornblum oxidation, named after Nathan Kornblum, is an organic redox reaction that converts alkyl halides and tosylates into carbonyl compounds, specifically aldehydes or ketones[1]. This reaction is particularly useful for the synthesis of carbonyl compounds from substrates such as benzylic and α-halo ketones. The process involves the formation of an alkoxysulfonium ion, which then undergoes an elimination reaction in the presence of a base, such as triethylamine (Et3N), to yield the carbonyl compound[1].

To improve the reaction's substrate scope, Kornblum later modified the procedure by converting the halide to a tosylate, which is a better leaving group, and using reagents like pyridine-N-oxide instead of dimethyl sulfoxide (DMSO). This modification led to the development of the Ganem oxidation, which expanded the use of various N-oxide reagents[1].

The Kornblum oxidation is one of the first DMSO oxidations and has been further developed with other oxidation methods such as the Pfitzner–Moffatt oxidation and Swern oxidation[2]. It is a valuable tool in organic synthesis, with applications ranging from the synthesis of potential plant-protecting compounds to the preparation of polymeric asymmetric ligands for use in catalysts[4].

The reaction mechanism is analogous to other DMSO-based oxidation reactions, producing dimethyl sulfide as a byproduct[12]. The general reaction mechanism involves the SN2 displacement of a primary halide by the oxygen of DMSO, followed by an elimination process to form the aldehyde[9].

In summary, the Kornblum oxidation is a significant method in organic chemistry for the synthesis of aldehydes from alkyl halides and tosylates, utilizing DMSO as a key reagent and generating carbonyl compounds through a base-promoted elimination mechanism.

Citations:

[1] https://en.wikipedia.org/wiki/Kornblum_oxidation

[2] https://www.sigmaaldrich.com/US/en/products/chemistry-and-biochemicals/chemical-synthesis/oxidation-reagents

[3] https://pubmed.ncbi.nlm.nih.gov/34746982/

[4] http://bch.ro/pdfRC/BRATULESCU%20G.pdf%208%2010.pdf

[5] https://www.sciencedirect.com/topics/chemistry/kornblum-oxidation

[6] https://pubs.acs.org/doi/10.1021/ja01524a080

[7] https://academic-accelerator.com/encyclopedia/kornblum-oxidation

[8] https://www.sciencedirect.com/science/article/abs/pii/S1001841707001398

[9] http://ursula.chem.yale.edu/~chem220/chem220js/STUDYAIDS/oxidation/DMSOoxidation~.html

[10] https://youtube.com/watch?v=x4PxxdW-PWo

[11] https://onlinelibrary.wiley.com/doi/10.1002/9780470638859.conrr373

[12] https://en.chem-station.com/reactions-2/2018/01/kornblum-oxidation.html

[13] https://youtube.com/watch?v=l2zkQYituy0

[14] https://www.chemeurope.com/en/encyclopedia/Kornblum_oxidation.html