Terminal-oxidant-free photocatalytic C–H alkylations of heteroarenes with alkylsilicates as alkyl radical precursors
作者:Gun Ikarashi、Tatsuya Morofuji、Naokazu Kano
DOI:10.1039/d0cc03286g
日期:——
Alkylsilicates bearing C,O-bidentate ligands could achieve photocatalytic C–H alkylations of heteroarenes under acidic conditions without adding any terminal oxidant.
Photoredox-Mediated Minisci-type Alkylation of <i>N</i>-Heteroarenes with Alkanes with High Methylene Selectivity
作者:Guo-Xing Li、Xiafei Hu、Gang He、Gong Chen
DOI:10.1021/acscatal.8b04079
日期:2018.12.7
We report a highly efficient and chemoselective Minisci-type alkylation reaction of N-heteroarenes with alkanes under the reagent control of a hypervalent iodine oxidant PFBI-OH. In addition to the high reactivity, PFBI-OH demonstrated a high steric sensitivity for H abstraction of alkanes. This reaction is selective for more sterically accessible secondary C–H bonds over weaker tertiary C–H bonds
Vinyl azides in heterocyclic synthesis. Part 5. Thermal and photochemical decomposition of azidocinnamates containing ortho-cycloalkylidene substituents
作者:Christopher J. Moody、Graham J. Warrellow
DOI:10.1039/p19870000913
日期:——
ortho-cycloalkylidene azidocinnamates (2b–e) in boiling toluene gives the indeno[1,2-b]tetrahydroazirines (8), derived by intramolecular ene reaction involving the CN bond of the intermediate 2H-azirines (11), as the major product. The intramolecular ene reaction is a highly favourable process, and also occurs at ca. 40 °C when the azirines (11) are formed by irradiation of the azides (2), although photochemical
在沸腾的甲苯中加热邻-亚环烷基叠氮吲哚酸酯(2b - e),得到茚并[1,2- b ]四氢叠氮化物(8),其是通过分子内烯反应涉及中间体2 H-叠氮基的C N键(11)制得的,作为主要产品。分子内烯反应是非常有利的过程,并且也发生在约200℃ 。当通过叠氮化物(2)的辐照形成叠氮化物(11)时,温度为40°C),尽管叠氮基的光化学开环确实存在竞争。仅当通过环亚烷基双键的环氧化消除了这种分子内烯反应的可能性时,才能以任何程度形成亚乙烯基衍生的产物,环氧叠氮化物(7)以高收率得到4-取代的吲哚(14)。
Vinyl azides in heterocyclic synthesis. Part 4. Thermal and photochemical decomposition of azidocinnamates containing ortho-cycloalkenyl substituents
作者:Christopher J. Moody、Graham J. Warrellow
DOI:10.1039/p19860001123
日期:——
Thermolysis of azidocinnamates containing ortho-cycloalkenyl substituents leads to isoquinolines and benzazepines formed by interception of the azide, or derived vinylnitrene, by the neighbouring double bond, the stability of the azide varying with the ring size of the cyclic alkene substituent. The cycloheptenyl (1a) and cyclopentenyl (1c) azidesdecompose at room temperature by intramolecular cycloaddition
Oxidase‐Type C−H/C−H Coupling Using an Isoquinoline‐Derived Organic Photocatalyst
作者:Lei Zhang、Björn Pfund、Oliver S. Wenger、Xile Hu
DOI:10.1002/anie.202202649
日期:2022.5.9
An isoquinoline-derived diaryl ketone-type photocatalyst was designed and synthesized. This photocatalyst enabled visible-light-mediated dehydrogenative cross-coupling of heteroarenes with alkanes and aldehydes using air as the sole oxidant. An unconventional mechanism with “self-quenching” to generate an isoquinoline N-radical cation to trigger hydrogen atom transfer (HAT) is involved, according to