493-08-3Relevant articles and documents
Photoredox catalysis on unactivated substrates with strongly reducing iridium photosensitizers
Shon, Jong-Hwa,Kim, Dooyoung,Rathnayake, Manjula D.,Sittel, Steven,Weaver, Jimmie,Teets, Thomas S.
, p. 4069 - 4078 (2021/04/06)
Photoredox catalysis has emerged as a powerful strategy in synthetic organic chemistry, but substrates that are difficult to reduce either require complex reaction conditions or are not amenable at all to photoredox transformations. In this work, we show that strong bis-cyclometalated iridium photoreductants with electron-rich β-diketiminate (NacNac) ancillary ligands enable high-yielding photoredox transformations of challenging substrates with very simple reaction conditions that require only a single sacrificial reagent. Using blue or green visible-light activation we demonstrate a variety of reactions, which include hydrodehalogenation, cyclization, intramolecular radical addition, and prenylationviaradical-mediated pathways, with optimized conditions that only require the photocatalyst and a sacrificial reductant/hydrogen atom donor. Many of these reactions involve organobromide and organochloride substrates which in the past have had limited utility in photoredox catalysis. This work paves the way for the continued expansion of the substrate scope in photoredox catalysis.
Intermediates for use in the preparation of vitamin e
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, (2008/06/13)
Novel intermediate compounds which can be used in the preparation of phytone and Vitamin E and a process for the preparation thereof. A process for the preparation of phytone and Vitamin E from these compounds is also claimed.
o-Benzoquinone Methide: An Intermediate in the Gas-Phase Pyrolysis of Chroman
Paul, Gitendra C.,Gajewski, Joseph J.
, p. 5060 - 5062 (2007/10/02)
Gas-phase pyrolysis of chroman gives o-cresol, benzofuran, and styrene in a 4:2:1 ratio at 413 deg C.In the presence of 2-butene, a moderately stereospecific 4 + 2 reaction occurs with the likely intermediate, o-benzoquinone methide, 1.The addition of 2-butene increased the amount of reaction and decreased the extent of formation of benzofuran and styrene.Addition of hydrogen gas increased the amount of hydrodealkoxylation product, styrene, and gave more of its reduction product, ethylbenzene, at the expense of benzofuran.Only a slight increase in the amount of o-cresol was observed upon addition of hydrogen gas.No dehydrochroman was observed in the reactions, and pyrolysis of 4H- and 2H-benzopyran gave no o-cresol, but instead gave styrene, benzofuran, 1-indanone, and some chroman.