18052-27-2Relevant articles and documents
Functionalization at Will of Rim-Differentiated Pillar[5]arenes
Demay-Drouhard, Paul,Du, Ke,Samanta, Kushal,Wan, Xintong,Yang, Weiwei,Srinivasan, Rajavel,Sue, Andrew C.-H.,Zuilhof, Han
, p. 3976 - 3980 (2019)
The development of an efficient synthetic route toward rim-differentiated C5-symmetric pillar[5]arenes (P[5]s), whose two rims are decorated with different chemical functionalities, opens up successive transformations of this macrocyclic scaffo
Synthesis of Bidentate Nitrogen Ligands by Rh-Catalyzed C-H Annulation and Their Application to Pd-Catalyzed Aerobic C-H Alkenylation
Kim, Hyun Tae,Kang, Eunsu,Kim, Minkyu,Joo, Jung Min
supporting information, p. 3657 - 3662 (2021/05/10)
A new class of bidentate ligands was prepared by a modular approach involving Rh-catalyzed C-H annulation reactions. The resulting conformationally constrained ligands enabled the Pd-catalyzed C-H alkenylation at electron-rich and sterically less hindered positions of electron-rich arenes while promoting the facile oxidation of Pd(0) intermediates by oxygen. This newly introduced ligand class is complementary to the ligands developed for Pd-catalyzed oxidative reactions and may find broad application in transition-metal-catalyzed reactions.
Silicon-Free SuFEx Reactions of Sulfonimidoyl Fluorides: Scope, Enantioselectivity, and Mechanism
Baggerman, Jacob,Jordaan, Daan,Liang, Dong-Dong,Streefkerk, Dieuwertje E.,Wagemakers, Jorden,Zuilhof, Han
supporting information, p. 7494 - 7500 (2020/03/23)
SuFEx reactions, in which an S?F moiety reacts with a silyl-protected phenol, have been developed as powerful click reactions. In the current paper we open up the potential of SuFEx reactions as enantioselective reactions, analyze the role of Si and outline the mechanism of this reaction. As a result, fast, high-yielding, “Si-free” and enantiospecific SuFEx reactions of sulfonimidoyl fluorides have been developed, and their mechanism shown, by both experimental and theoretical methods, to yield chiral products.
Ligand-Promoted Non-Directed C?H Cyanation of Arenes
Liu, Luo-Yan,Yeung, Kap-Sun,Yu, Jin-Quan
supporting information, p. 2199 - 2202 (2019/01/24)
This article reports the first example of a 2-pyridone accelerated non-directed C?H cyanation with an arene as the limiting reagent. This protocol is compatible with a broad scope of arenes, including advanced intermediates, drug molecules, and natural products. A kinetic isotope experiment (kH/kD=4.40) indicates that the C?H bond cleavage is the rate-limiting step. Also, the reaction is readily scalable, further showcasing the synthetic utility of this method.
H-D Exchange Deuteration of Arenes at Room Temperature
Sawama, Yoshinari,Nakano, Akihiro,Matsuda, Takumi,Kawajiri, Takahiro,Yamada, Tsuyoshi,Sajiki, Hironao
supporting information, p. 648 - 653 (2019/02/14)
Arene nuclei efficiently underwent the hydrogen (H)-deuterium (D) exchange reaction catalyzed by platinum group metals on carbon in a mixed solvent of 2-propanol and D2O at room temperature to produce deuterium-labeled arenes. Platinum on carbon (Pt/C) and iridium on carbon (Ir/C) were applicable catalysts, and the various arenes bearing a carbonyl group, fluorine, phenolic hydroxy group, amino group, or phosphonic acid on the aromatic nucleus were effectively deuterated. Nonheating conditions are valuable for the scalable industrial preparation.
A general copper-based photoredox catalyst for organic synthesis: Scope, application in natural product synthesis and mechanistic insights
Deldaele, Christopher,Michelet, Bastien,Baguia, Hajar,Kajouj, Sofia,Romero, Eugenie,Moucheron, Cecile,Evano, Gwilherm
, p. 621 - 629 (2018/10/04)
Organic transformations can broadly be classified into four categories including cationic, anionic, pericyclic and radical reactions. While the last category has been known for decades to provide remarkably efficient synthetic pathways, it has long been hampered by the need for toxic reagents, which considerably limited its impact on chemical synthesis. This situation has come to an end with the introduction of new concepts for the generation of radical species, photoredox catalysis – which simply relies on the use of a catalyst that can be activated upon visible light irradiation – certainly being the most efficient one. The state-of-the-art catalysts mostly rely on the use of ruthenium and iridium complexes and organic dyes, which still considerably limits their broad implementation in chemical processes: alternative readily available catalysts based on inexpensive, environmentally benign base metals are therefore strongly needed. Furthermore, expanding the toolbox of methods based on photoredox catalysis will facilitate the discovery of new light-mediated transformations. This article details the use of a simple copper complex which, upon activation with blue light, can initiate a broad range of radical reactions.
Mild synthesis of silyl ethers: Via potassium carbonate catalyzed reactions between alcohols and hydrosilanes
Delucia, Nicholas A.,Das, Nivedita,Vannucci, Aaron K.
, p. 3415 - 3418 (2018/05/23)
A method has been developed for the silanolysis of alcohols using an abundant and non-corrosive base K2CO3 as a catalyst. Reactions between a variety of alcohols and hydrosilanes generate silyl ethers under mild conditions. The use of hydrosilanes leads to the formation of H2 as the only byproduct thus avoiding the formation of stoichiometric strong acids. The mild conditions lead to a wide scope of possible alcohol substrates and good functional group tolerance. Selective alcohol silanolysis is also observed in the presence of reactive C-H bonds, lending this method for extensive use in protection group chemistry.
A General Copper Catalyst for Photoredox Transformations of Organic Halides
Michelet, Bastien,Deldaele, Christopher,Kajouj, Sofia,Moucheron, Cécile,Evano, Gwilherm
supporting information, p. 3576 - 3579 (2017/07/17)
A broadly applicable copper catalyst for photoredox transformations of organic halides is reported. Upon visible light irradiation in the presence of catalytic amounts of [(DPEphos)(bcp)Cu]PF6 and an amine, a range of unactivated aryl and alkyl halides were shown to be smoothly activated through a rare Cu(I)/Cu(I)?/Cu(0) catalytic cycle. This complex efficiently catalyzes a series of radical processes, including reductions, cyclizations, and direct arylation of arenes.
Minimal Self-Immolative Probe for Multimodal Fluoride Detection
Gabrielli, Luca,Mancin, Fabrizio
, p. 10715 - 10720 (2016/11/29)
Two single-molecule, self-immolative fluoride probes, namely tert-butyldimethylsilyl-protected 2- and 4-difluoromethylphenol, are described. Compared to similar systems previously described, the probes are characterized by a simpler structure and straightforward, two-step preparation. Nevertheless, they allow the detection of fluoride ions at micromolar concentration by the naked eye, UV-vis absorption, and fluorescence. A detailed investigation of the self-immolative reaction reveals that the rate-limiting step is the release of the first fluoride ion from the difluoromethylphenolate intermediate. Moreover, the mutual position of the difluoromethyl- and tert-butyldimethylsilyl-protected residues has a relevant effect on the reactivity. Likely, a CF2H-O hydrogen bond in the 2-isomer increases the reactivity of the silyl ether toward hydrolytic cleavage but also stabilizes the phenolate intermediate, slowing the release of fluoride ions.
The Hexachlorocerate(III) Anion: A Potent, Benchtop Stable, and Readily Available Ultraviolet A Photosensitizer for Aryl Chlorides
Yin, Haolin,Jin, Yi,Hertzog, Jerald E.,Mullane, Kimberly C.,Carroll, Patrick J.,Manor, Brian C.,Anna, Jessica M.,Schelter, Eric J.
supporting information, p. 16266 - 16273 (2016/12/27)
The hexachlorocerate(III) anion, [CeIIICl6]3-, was found to be a potent photoreductant in acetonitrile solution with an estimated excited-state reduction potential of - 3.45 V versus Cp2Fe0/+. Despite a short lifetime of 22.1(1) ns, the anion exhibited a photoluminescence quantum yield of 0.61(4) and fast quenching kinetics toward organohalogens allowing for its application in the photocatalytic reduction of aryl chloride substrates.
