Copper-Catalyzed Synthesis of Azaspirocyclohexadienones from α-Azido-<i>N</i>-arylamides under an Oxygen Atmosphere
作者:Shunsuke Chiba、Line Zhang、Jian-Yuan Lee
DOI:10.1021/ja1027327
日期:2010.6.2
copper-catalyzed reaction of alpha-azido-N-arylamides was found to proceed under an oxygen atmosphere to afford azaspirocyclohexadienones. The present transformation is carried out by a sequence of denitrogenative formation of iminyl copper species from alpha-azido-N-arylamides and their imino-cupration with an intramolecular benzene ring on the amido nitrogen followed by consecutive formation of C=O bonds. The
paper reports on the selective conversion of alkyl azido groups at the carbonyl α-position to diazo compounds. Through β-elimination of dinitrogen, followed by hydrazone formation/decomposition, α-azidocarbonyl moieties were transformed into α-diazo carbonyl groups in one step. As these reaction conditions do not involve aryl or general alkyl azides, site-selective conversions of di- and triazides were
<i>tert-</i>Butyl Hydroperoxide and Tetrabutylammonium Iodide-Promoted Free Radical Cyclization of α-Imino-<i>N</i>-arylamides and α-Azido-<i>N</i>-arylamides
作者:Dianjun Li、Tonghao Yang、Hailin Su、Wei Yu
DOI:10.1002/adsc.201500305
日期:2015.8.10
The oxidizing system of tert‐butyl hydroperoxide (TBHP) and tetrabutylammonium iodide (TBAI) is capable of generating α‐(arylaminocarbonyl)iminyl radicals from ethyl 2‐(N‐arylcarbamoyl)‐2‐iminoacetates. These iminyl radicals preferably undergo intramolecular ipso attack on the benzene ring to give azaspirocyclohexadienyl radicals, which are readily captured by molecular oxygen under an oxygen atmosphere
This paper reports the selective conversion of alkyl azido groups at the carbonyl α-position into oximes through β-elimination of dinitrogen, followed by transoximation. With this method and diazo conversion, a triazido molecule was transformed into a triple click conjugation scaffold allowing one-pot four-component coupling.
Photoredox‐Catalyzed Tandem Demethylation of
<i>N</i>
,
<i>N</i>
‐Dimethyl Anilines Followed by Amidation with α‐Keto or Alkynyl Carboxylic Acids
作者:Pritha Das、Hasina Mamataj Begam、Samir Kumar Bhunia、Ranjan Jana
DOI:10.1002/adsc.201900525
日期:2019.9.3
for highly selective monodemethylation of N,N‐dimethyl anilines to generate secondary amines and subsequent coupling with α‐ketocarboxylic acids or alkynyl carboxylic acids to form α‐ketoamides or alkynamides respectively undervisiblelight photoredox catalyst in a single operation. From the deuterium‐labeling experiment, it was probed that demethylation is the slowest step in this tandem process