330-12-1Relevant articles and documents
1,2-Dibutoxyethane-Promoted Oxidative Cleavage of Olefins into Carboxylic Acids Using O2 under Clean Conditions
Ou, Jinhua,Tan, Hong,He, Saiyu,Wang, Wei,Hu, Bonian,Yu, Gang,Liu, Kaijian
, p. 14974 - 14982 (2021/10/25)
Herein, we report the first example of an effective and green approach for the oxidative cleavage of olefins to carboxylic acids using a 1,2-dibutoxyethane/O2 system under clean conditions. This novel oxidation system also has excellent functional-group tolerance and is applicable for large-scale synthesis. The target products were prepared in good to excellent yields by a one-pot sequential transformation without an external initiator, catalyst, and additive.
An Anionic, Chelating C(sp3)/NHC ligand from the Combination of an N-heterobicyclic Carbene and Barbituric Heterocycle
Benaissa, Idir,Gajda, Katarzyna,Vendier, Laure,Lugan, No?l,Kajetanowicz, Anna,Grela, Karol,Michelet, Véronique,César, Vincent,Bastin, Stéphanie
supporting information, p. 3223 - 3234 (2021/09/30)
The coordination chemistry of the anionic NHC1-based on an imidazo[1,5-a]pyridin-3-ylidene (IPy) platform substituted at the C5 position by an anionic barbituric heterocycle was studied with d6(Ru(II), Mn(I)) and d8(Pd(II), Rh(I), Ir(I), Au(III)) transition-metal centers. While the anionic barbituric heterocycle is planar in the zwitterionic NHC precursor 1·H, NMR spectroscopic analyses supplemented by X-ray diffraction studies evidenced the chelating behavior of ligand 1-through the carbenic and the malonic carbon atoms in all of the complexes, resulting from a deformation of the lateral barbituric heterocycle. The complexes were obtained by reaction of the free carbene with the appropriate metal precursor, except for the Au(III) complex 10, which was obtained by oxidation of the antecedent gold(I) complex [AuCl(1)]?with PhICl2as an external oxidant. During the course of the process, the kinetic gold(I) intermediate 9 resulting from the oxidation of the malonic carbon of the barbituric moiety was isolated upon crystallization from the reaction mixture. The νCOstretching frequencies recorded for complex [Rh(1)(CO)2] (5) demonstrated the strong donating character of the malonate-C(sp3)/NHC ligand 1-. The ruthenium complex [Ru(1)Cl(p-cymene)] (11) was implemented as a precatalyst in the dehydrogenative synthesis of carboxylic acid derivatives from primary alcohols and exhibited high activities at low catalyst loadings (25-250 ppm) and a large tolerance toward functional groups.
Radical C?H Trifluoromethoxylation of (Hetero)arenes with Bis(trifluoromethyl)peroxide
Dix, Stefan,Golz, Paul,Schmid, Jonas R.,Riedel, Sebastian,Hopkinson, Matthew N.
supporting information, p. 11554 - 11558 (2021/07/09)
Trifluoromethoxylated (hetero)arenes are of great interest for several disciplines, especially in agro- and medicinal chemistry. Radical C?H trifluoromethoxylation of (hetero)arenes represents an attractive approach to prepare such compounds, but the high cost and low atom economy of existing .OCF3 radical sources make them unsuitable for the large-scale synthesis of trifluoromethoxylated building blocks. Herein, we introduce bis(trifluoromethyl)peroxide (BTMP, CF3OOCF3) as a practical and efficient trifluoromethoxylating reagent that is easily accessible from inexpensive bulk chemicals. Using either visible light photoredox or TEMPO catalysis, trifluoromethoxylated arenes could be prepared in good yields under mild conditions directly from unactivated aromatics. Moreover, TEMPO catalysis allowed for the one-step synthesis of valuable pyridine derivatives, which have been previously prepared via multi-step approaches.
Milled Dry Ice as a C1 Source for the Carboxylation of Aryl Halides
O'Brien, Connor J.,Nicewicz, David A.
supporting information, p. 814 - 816 (2021/03/01)
The use of carbon dioxide as a C1 chemical feedstock remains an active field of research. Here we showcase the use of milled dry ice as a method to promote the availability of CO 2in a reaction solution, permitting practical synthesis of arylcarboxylic acids. Notably, the use of milled dry ice produces marked increases in yields relative to those obtained with gaseous CO 2, as previously reported in the literature.
Photocatalytic trifluoromethoxylation of arenes and heteroarenes in continuous-flow
Cendón, Borja,Gulías, Moisés,Ho, Michelle,No?l, Timothy,Nyuchev, Alexander V.,Sambiagio, Carlo,Struijs, Job J. C.,Wan, Ting,Wang, Ying
supporting information, p. 1305 - 1312 (2020/07/10)
The first example of photocatalytic trifluoromethoxylation of arenes and heteroarenes under continuous-flow conditions is described. Application of continuous-flow microreactor technology allowed to reduce the residence time up to 16 times in comparison t
CO2 (De)Activation in Carboxylation Reactions: A Case Study Using Grignard Reagents and Nucleophilic Bases
Valera Lauridsen, Jerik Mathew,Cho, Sung Yeon,Bae, Han Yong,Lee, Ji-Woong
supporting information, p. 1652 - 1657 (2020/03/30)
Carbon dioxide (CO2) is an intrinsically stable molecule. However, its reactivity toward nucleophilic bases has constituted an appealing characteristic for applications such as CO2 capture and functionalization. To shed light on the role of nucleophilic bases in CO2 functionalization, we performed some mechanistic studies using nitrogen-containing bases as an additive-in catalytic amounts-for carboxylation reactions of Grignard reagents. Our kinetic analysis and in situ infrared spectroscopy revealed the role of nucleophilic bases, particularly that of DBU (1,8-diazabicycloundec-7-ene), in CO2 (de)activation for carboxylation reactions.
Carboxylation of Aryl Triflates with CO2 Merging Palladium and Visible-Light-Photoredox Catalysts
Bhunia, Samir Kumar,Das, Pritha,Nandi, Shantanu,Jana, Ranjan
supporting information, p. 4632 - 4637 (2019/06/27)
We report herein a visible-light-promoted, highly practical carboxylation of readily accessible aryl triflates at ambient temperature and a balloon pressure of CO2 by the combined use of palladium and photoredox Ir(III) catalysts. Strikingly, the stoichiometric metallic reductant is replaced by a nonmetallic amine reductant providing an environmentally benign carboxylation process. In addition, one-pot synthesis of a carboxylic acid directly from phenol and modification of estrone and concise synthesis of pharmaceutical drugs adapalene and bexarotene have been accomplished via late-stage carboxylation reaction. Furthermore, a parallel decarboxylation-carboxylation reaction has been demonstrated in an H-type closed vessel that is an interesting concept for the strategic sector. Spectroscopic and spectroelectrochemical studies indicated electron transfer from the Ir(III)/DIPEA combination to generate aryl carboxylate and Pd(0) for catalytic turnover.
DIFLUOROMETHOXYLATION AND TRIFLUOROMETHOXYLATION COMPOSITIONS AND METHODS FOR SYNTHESIZING SAME
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Page/Page column 75; 79; 118; 119; 123-124, (2019/09/18)
The present invention provides a compound having the structure (I), a processing of making the compound; and a process of using the compound as a reagent for the difluoromethoxylation and trifluoromethoxylation of arenes or heteroarenes.
Highly active bidentate N-heterocyclic carbene/ruthenium complexes performing dehydrogenative coupling of alcohols and hydroxides in open air
Wang, Zhi-Qin,Tang, Xiao-Sheng,Yang, Zhao-Qi,Yu, Bao-Yi,Wang, Hua-Jing,Sang, Wei,Yuan, Ye,Chen, Cheng,Verpoort, Francis
supporting information, p. 8591 - 8594 (2019/07/25)
Eight bidentate NHC/Ru complexes, namely [Ru]-1-[Ru]-8, were designed and prepared. In particular, [Ru]-2 displayed extraordinary performance even in open air for the dehydrogenative coupling of alcohols and hydroxides. Notably, an unprecedentedly low catalyst loading of 250 ppm and the highest TON of 32 800 and TOF of 3200 until now were obtained.
Redox-Active Reagents for Photocatalytic Generation of the OCF3 Radical and (Hetero)Aryl C?H Trifluoromethoxylation
Zheng, Weijia,Lee, Johnny W.,Morales-Rivera, Cristian A.,Liu, Peng,Ngai, Ming-Yu
supporting information, p. 13795 - 13799 (2018/09/27)
The trifluoromethoxy (OCF3) radical is of great importance in organic chemistry. Yet, the catalytic and selective generation of this radical at room temperature and pressure remains a longstanding challenge. Herein, the design and development of a redox-active cationic reagent (1) that enables the formation of the OCF3 radical in a controllable, selective, and catalytic fashion under visible-light photocatalytic conditions is reported. More importantly, the reagent allows catalytic, intermolecular C?H trifluoromethoxylation of a broad array of (hetero)arenes and biorelevant compounds. Experimental and computational studies suggest single electron transfer (SET) from excited photoredox catalysts to 1 resulting in exclusive liberation of the OCF3 radical. Addition of this radical to (hetero)arenes gives trifluoromethoxylated cyclohexadienyl radicals that are oxidized and deprotonated to afford the products of trifluoromethoxylation.
