Selective Oxidative Homo- and Cross-Coupling of Phenols with Aerobic Catalysts
摘要:
Simple catalysts that use atom-economical oxygen as the terminal oxidant to accomplish selective ortho-ortho, ortho-para, or para-para homo-couplings of phenols are described. In addition, chromium salen catalysts have been discovered as uniquely effective in the cross-coupling of different phenols with high chemo- and regioselectivity.
Irreversible inhibitors of G12C mutant K-Ras protein are provided. Also disclosed are methods to modulate the activity of G12C mutant K-Ras protein and methods of treatment of disorders mediated by G12C mutant K-Ras protein.
Enantioselective Vanadium-Catalyzed Oxidative Coupling: Development and Mechanistic Insights
作者:Houng Kang、Madison R. Herling、Kyle A. Niederer、Young Eun Lee、Peddiahgari Vasu Govardhana Reddy、Sangeeta Dey、Scott E. Allen、Paul Sung、Kirsten Hewitt、Carilyn Torruellas、Gina J. Kim、Marisa C. Kozlowski
DOI:10.1021/acs.joc.8b02083
日期:2018.12.7
vanadium catalyst for enantioselectiveoxidativecoupling of phenols is reported, ultimately resulting in a simple monomeric vanadium species combined with a Brønsted or Lewis acid additive. The resultant vanadium complex is found to effect the asymmetric oxidative ortho–ortho coupling of simple phenols and 2-hydroxycarbazoles with good to excellent levels of enantioselectivity. Experimental and quantum
Facile and Reliable Synthesis of Tetraphenoxyborates and Their Properties
作者:Itamar M. Malkowsky、Roland Fröhlich、Ulrich Griesbach、Hermann Pütter、Siegfried R. Waldvogel
DOI:10.1002/ejic.200600074
日期:2006.4
Tetraphenoxyborates are reliably prepared in a two-step sequence, exploiting less corrosive reagents like boric acid and the corresponding phenols. The broad scope of this transformation is demonstrated in 22 examples. Several solid-state structures reveal the preferential conformation of the phenoxy moieties allowing cation interaction. Furthermore, a novel architecture of a phenoxy-substituted tetraborate
Facile and Selective Cross-Coupling of Phenols Using Selenium Dioxide
作者:Thomas Quell、Nicole Beiser、Katrin M. Dyballa、Robert Franke、Siegfried R. Waldvogel
DOI:10.1002/ejoc.201600886
日期:2016.9
Therefore, an easy and versatile protocol for oxidative cross-coupling is essential to generate these so-called “privileged ligands”. We developed an efficient and selective oxidative pathway to synthesize 2,2′-biphenols as well as 2,4′- and 4,4′-biphenols. The use of selenium dioxide, a stable, powerful, and commercially available oxidizer, in 1,1,1,3,3,3-hexafluoroisopropanol allowed the oxidative coupling
Titanium Tetrachloride Induced Fries Rearrangement: A New Route to Disubstituted 2′- Hydroxypropiophenones
作者:Robert Martin、Pierre Demerseman
DOI:10.1055/s-1989-27134
日期:——
Fries rearrangement of some dialkylphenyl propionates with titanium tetrachloride proves to be a convenient route to hindered dialkyl 2′-hydroxypropiophenones. The sequential use of soft titanium tetrachloride to perform the Fries rearrangement followed by hard aluminum chloride to achieve the elimination of a protecting tert-butyl group allows the synthesis of some previously unknown 3′,6′- and 5′,6′-dialkyl-2-hydroxypropiophenones.