Julia-Kociensky Olefination
The Julia-Kocienski Olefination is a chemical reaction used in organic chemistry for the preparation of alkenes. It is a modified version of the Julia-Lythgoe olefination, named after the French chemist Marc Julia and further refined by Philip Joseph Kocienski[5].
In this reaction, benzothiazol-2-yl sulfones are used to prepare alkenes from aldehydes in a single step[1]. The reaction involves the addition of a sulfonyl-stabilized carbanion to a carbonyl compound, followed by elimination to form an alkene[5].
The Julia-Kocienski Olefination offers very high selectivity and yields for BT and PT sulfones in various solvents, where they are first metalated with various bases and then reacted with an aldehyde[1]. This reaction often generates a mixture of alkene stereoisomers[5].
The Julia-Kocienski Olefination is also used for the synthesis of fluorovinyl compounds[3]. The reaction of α-fluorinated heteroaryl or electron-deficient aryl sulfones with a variety of carbonyls takes place in a Julia–Kocienski olefination model[10].
The mechanism of the Julia-Kocienski Olefination involves the initial addition of the sulfonyl anion to the aldehyde, which is not reversible[1]. The mechanism also involves intramolecular attack of the alkoxide intermediate to the tetrazole ring and elimination (the Smiles rearrangement)[13].
The Julia-Kocienski Olefination is a versatile platform for the synthesis of various fluorinated compounds[3]. It is capable of generating a wide variety of complex alkene targets[11]. Despite its popularity, the use of the modified Julia-Kocienski olefination for the preparation of fluorovinyl compounds has been reported[3].
In conclusion, the Julia-Kocienski Olefination is a valuable tool in organic chemistry for the synthesis of alkenes, offering high selectivity and yields. It is particularly useful for the synthesis of fluorinated compounds.
Citations:
[1] https://www.organic-chemistry.org/namedreactions/modified-julia-kocienski-olefination.shtm
[2] https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/slct.202200760
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3337086/
[4] https://pubs.acs.org/doi/10.1021/acsomega.2c03732
[5] https://en.wikipedia.org/wiki/Julia_olefination
[6] https://www.researchgate.net/publication/362783433_Recent_Applications_and_Trends_in_the_Julia-Kocienski_Olefination
[7] https://www.sciencedirect.com/science/article/abs/pii/S0040402009004220
[8] https://www.organic-chemistry.org/namedreactions/julia-olefination.shtm
[9] https://pubs.acs.org/doi/abs/10.1021/acs.orglett.6b02160
[10] https://www.sciencedirect.com/topics/chemistry/julia-kocienski-olefination
[11] http://sites.science.oregonstate.edu/chemistry/blakemore/Downloads/Julia_Kocienski_olefination(unofficial).pdf
[12] https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/ejoc.202201217?af=R
[13] https://en.chem-station.com/reactions-2/2015/11/julia-kocienski-olefination.html
[14] https://chemistry-europe.onlinelibrary.wiley.com/doi/pdf/10.1002/ejoc.202201217