protocol for direct C–H alkylation and acylation of N-heterocycles, using readily accessible carboxylic acids as radical precursors under visible-light irradiation without a photocatalyst and an additional acid additive, has been developed. This protocol provides expedient access to substituted N-heterocycles under mild and metal-free conditions. Mechanistic experiments indicate that this reaction proceeds
Direct Selective Oxidative Cross-Coupling of Simple Alkanes with Heteroarenes
作者:Andrey P. Antonchick、Lars Burgmann
DOI:10.1002/anie.201209584
日期:2013.3.11
A dream reaction: An efficient and practical method for the oxidative cross‐coupling of heteroaromatic compounds and simplealkanes has been developed. The desired products are smoothly and regioselectively formed under mild reaction conditions at ambient temperature in a hypervalent‐iodine‐mediated transformation. The method allows for preferential transformation of stronger CH bonds in the presence
The reactions of dioxanyl and cyclohexylradicals with 2- and 3-X-pyridines (X = CN, COMe, CO2Me) give a single substitution product deriving by addition at the 5- and 6-positions respectively; with 4-X-pyridines substitution occurs preferentially at the 3-position. If the reactions are carried out with protonated pyridines other positional isomers are obtained. From the synthetic point of view the
Ketone-derived 2,3-dihydroquinazolinones in <i>N</i>-heteroarene C–H alkylation <i>via</i> C–C bond scission under oxidative metal catalysis
作者:Pinku Prasad Mondal、Amit Pal、Athira K Prakash、Basudev Sahoo
DOI:10.1039/d2cc04947c
日期:——
activation of pre-aromatic 2,3-dihydroquinazolinone to generate an alkyl radical, supported by mechanistic studies. In addition to the broad scope, good functionality tolerance, late stage functionalization of APIs, and synthesis of a novel Papaverine analogue, the utilization of an N-heteroarene C–H bond and ketone as a non-trivial alkyl radical source represents the salient feature of this method.
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