CuBr2-Promoted Tetrahydrofuranylation of Alcohols and 1,3-Dione
摘要:
A method for the CuBr2-promoted tetrahydrofuranylation of alcohols and 1,3-dione has been developed. A variety of different alcohols were efficiently converted into the corresponding 2-tetrahydrofuran ethers in the presence of CuBr2. It is noteworthy that this protocol also successfully converted 1,3-diphenyl-1,3-dione into the corresponding 2-tetrahydrofuran derivative in good yield.
Light-promoted metal-free cross dehydrogenative couplings on ethers mediated by NFSI: reactivity and mechanistic studies
作者:Redouane Beniazza、Baptiste Abadie、Lionel Remisse、Damien Jardel、Dominique Lastécouères、Jean-Marc Vincent
DOI:10.1039/c7cc05854c
日期:——
Cross dehydrogenative couplings on ethers occur very effectively using N-fluorobis(phenyl)sulfonimide (NFSI) as oxidizingagent under UVA irradiation in the presence of 2 mol% benzophenone. The reaction was shown to proceed first by fast radical fluorination of the α-C–H bond of ethers, followed by HF elimination to yield the highly electrophilic oxocarbenium ion as a key intermediate.
Photochemical C–H acetalization of O-heterocycles utilizing phenylglyoxylic acid as the photoinitiator
作者:Giorgos S. Koutoulogenis、Nikoleta Spiliopoulou、Christoforos G. Kokotos
DOI:10.1007/s43630-021-00126-7
日期:2022.5
easy-to-execute procedure for the C-H acetalization of O-heterocycles via visible light activation is presented, utilizing phenylglyoxylic acid as the photoinitiator. Biomass-derived O-heterocycles, like THF, can be employed, while primary, secondary alcohols and alcohols bearing a variety of functionalities were succesfully employed, affording the desired acetals in high yields. Facile acidic deprotection
Trialkylphosphonium oxoborates as C(sp<sup>3</sup>)–H oxyanion holes and their application in catalytic chemoselective acetalization
作者:Vincent Ming-Yau Leung、Hong-Chai Fabio Wong、Chun-Man Pook、Ying-Lung Steve Tse、Ying-Yeung Yeung
DOI:10.1039/d3sc03081d
日期:——
borate counter anion in a TOB catalyst increases the availability of C(sp3)–H to interact with electron donor substrates. The catalytic protocol is applicable to a wide range of substrates in the acetalization reaction and provides excellent chemoselectivity in the acetalization over thioacetalization in the presence of alcohols and thiols, which is otherwise hard to achieve using typical acid catalysts