Accessing Difluoromethylated and Trifluoromethylated
<i>cis</i>
‐Cycloalkanes and Saturated Heterocycles: Preferential Hydrogen Addition to the Substitution Sites for Dearomatization
作者:Xue Zhang、Liang Ling、Meiming Luo、Xiaoming Zeng
DOI:10.1002/anie.201907457
日期:2019.11.18
Reported here is a straightforward process in which a cyclic (alkyl)(amino)carbene/Rh catalyst system facilitates the preferential addition of hydrogen to the substitutionsites of difluoromethylated and trifluoromethylated arenes and heteroarenes, leading to dearomative reduction. This strategy enables the diastereoselective synthesis of cis-difluoromethylated and cis-trifluoromethylated cycloalkanes
An Annulative Synthetic Strategy for Building Triphenylene Frameworks by Multiple C−H Bond Activations
作者:Bijoy P. Mathew、Hyun Ji Yang、Joohee Kim、Jae Bin Lee、Yun-Tae Kim、Sungmin Lee、Chang Young Lee、Wonyoung Choe、Kyungjae Myung、Jang-Ung Park、Sung You Hong
DOI:10.1002/anie.201700405
日期:2017.4.24
C−H activation is a versatile tool for appending aryl groups to aromatic systems. However, heavy demands on multiple catalytic cycle operations and site‐selectivity have limited its use for graphene segment synthesis. A Pd‐catal‐ yzed one‐step synthesis of functionalized triphenylene frameworks is disclosed, which proceeds by 2‐ or 4‐fold C−H arylation of unactivated benzene derivatives. A Pd2(dibenzylideneacetone)3
Visible-light-induced Pd-catalyzed <i>ortho</i>-trifluoromethylation of acetanilides with CF<sub>3</sub>SO<sub>2</sub>Na under ambient conditions in the absence of an external photocatalyst
作者:Long Zou、Pinhua Li、Bin Wang、Lei Wang
DOI:10.1039/c9cc01014a
日期:——
A visible-light-induced Pd-catalyzed ortho-trifluoromethylation of acetanilides with CF3SO2Na without any external photocatalyst or additive was developed.
Carbonylation of various organolithium reagents. A novel approach to heterocycles via intramolecular trapping of aromatic acyllithiums
作者:Keith Smith、Gamal A. El-Hiti、Gareth J. Pritchard、Anna Hamilton
DOI:10.1039/a903467f
日期:——
Doubly lithiated N-pivaloylanilines react smoothly with carbon monoxide at 0 °C to give 3-tert-butyl-3-hydroxy-2,3-dihydroindol-2-ones in good yields. Similarly, carbonylation of doubly lithiated 4-pivaloylamino- and 2-pivaloylaminopyridines at 0 °C affords the corresponding 5-aza- and 7-aza-3-tert-butyl-3-hydroxy-2,3-dihydroindol-2-ones, respectively, in good yields. However, carbonylation of doubly lithiated N-pivaloyl-o-toluidines takes a different course due to direct intramolecular cyclisation of the dilithio reagents to afford 2-tert-butylindoles without uptake of carbon monoxide.
Rhodium(III)-catalysed, redox-neutral C(sp2)-H alkenylation using pivalimide as a directing group with internal alkynes
作者:Subban Kathiravan、Ian A. Nicholls
DOI:10.1016/j.tetlet.2016.11.039
日期:2017.1
In the presence of [RhCp∗Cl2]2, N-pivaloyl anilines react with internal alkynes to give the corresponding 2-alkenylpivalimides under redox neutral conditions through C-H activation. This redox neutral hydroarylation, which does not require an external organic acid, unlocks a regioselective synthetic route to 2-alkenyl anilines and is generally applicable to diversely substituted electron rich and electron