Ethynyl Benziodoxolones for the Direct Alkynylation of Heterocycles: Structural Requirement, Improved Procedure for Pyrroles, and Insights into the Mechanism
作者:Jonathan P. Brand、Clara Chevalley、Rosario Scopelliti、Jérôme Waser
DOI:10.1002/chem.201200200
日期:2012.4.27
accelerating effect of a methyl substituent in both the 3‐ and 6‐position of triisopropylsilylethynyl‐1,2‐benziodoxol‐3(1H)‐one (TIPS‐EBX) on the reaction rate was observed. Competitive experiments between substrates of different nucleophilicity, deuterium labeling experiments, as well as the regioselectivity observed are all in agreement with electrophilic aromatic substitution. Gold(III) 2‐pyridinecarboxylate
Photochemical Functionalization of Heterocycles with EBX Reagents: C−H Alkynylation versus Deconstructive Ring Cleavage**
作者:Errika Voutyritsa、Marion Garreau、Maroula G. Kokotou、Ierasia Triandafillidi、Jérôme Waser、Christoforos G. Kokotos
DOI:10.1002/chem.202002868
日期:2020.11.11
The development of novel methodologies for the functionalization of saturated heterocycles is highly desirable. Herein, we report a cheap and efficient photochemical method for the C−H functionalization of saturated O‐heterocycles, as well as the deconstructive ring‐cleavage of S‐heterocycles, employing hypervalent iodine alkynylation reagents (ethynylbenziodoxolones, EBX). This photochemical alkynylation
Room-Temperature Decarboxylative Alkynylation of Carboxylic Acids Using Photoredox Catalysis and EBX Reagents
作者:Franck Le Vaillant、Thibaut Courant、Jerome Waser
DOI:10.1002/anie.201505111
日期:2015.9.14
ethynylbenziodoxolone (EBX) reagents allowed the decarboxylativealkynylation of carboxylicacids in good yields under mild conditions. The method could be applied to silyl‐, aryl‐, and alkyl‐ substituted alkynes. It was particularly successful in the case of α‐amino and α‐oxo acids derived from biomass.
Gold‐Catalyzed Stereoselective Domino Cyclization/Alkynylation of
<i>N</i>
‐Propargylcarboxamides with Benziodoxole Reagents for the Synthesis of Alkynyloxazolines
作者:Ximei Zhao、Bing Tian、Yangyang Yang、Xiaojia Si、Florian F. Mulks、Matthias Rudolph、Frank Rominger、A. Stephen K. Hashmi
DOI:10.1002/adsc.201900264
日期:2019.7.2
highly stereoselectivesynthesis of alkynyloxazolines via a gold‐catalyzed domino cyclization‐alkynylation cascade of N‐propargylcarboxamides with benziodoxole reagents is reported. This new protocol, which represents an attractive alternative to two step sequences based on Sonagashira couplings, offers a broad substrate scope, excellent functional group tolerance, and perfect stereoselectivity. A comparison
Gold-Catalyzed 1,2-Oxyalkynylation of <i>N</i>-Allenamides with Ethylnylbenziodoxolones
作者:Somsuvra Banerjee、Beeran Senthilkumar、Nitin T. Patil
DOI:10.1021/acs.orglett.8b03651
日期:2019.1.4
redox-neutral Au(I)/Au(III) catalytic pathway, was enabled in an attempt to exhaust the EBX reagents atom-economically by putting the nucleophilic carboxylate part of EBXs to appropriate use. This constitutes the first example for gold-catalyzed β-alkynylation of N-allenamides to construct highly valuable 1,3-enynes. The potential of the sequence is further documented by some follow-up transformations