118804-25-4Relevant academic research and scientific papers
Synthesis of Triarylmethanes via Palladium-Catalyzed Suzuki-Miyaura Reactions of Diarylmethyl Esters
Dardir, Amira H.,Casademont-Reig, Irene,Balcells, David,Ellefsen, Jonathan D.,Espinosa, Matthew R.,Hazari, Nilay,Smith, Nicholas E.
, p. 2332 - 2344 (2021/06/28)
The synthesis of triarylmethanes via Pd-catalyzed Suzuki-Miyaura reactions between diarylmethyl 2,3,4,5,6-pentafluorobenzoates and aryl boronic acids is described. The system operates under mild conditions and has a broad substrate scope, including the coupling of diphenylmethanol derivatives that do not contain extended aromatic substituents. This is significant as these substrates, which result in the types of triarylmethane products that are prevalent in pharmaceuticals, have not previously been compatible with systems for diarylmethyl ester coupling. Furthermore, the reaction can be performed stereospecifically to generate stereoinverted products. On the basis of DFT calculations, it is proposed that the oxidative addition of the diarylmethyl 2,3,4,5,6-pentafluorobenzoate substrate occurs via an SN2 pathway, which results in the inverted products. Mechanistic studies indicate that oxidative addition of the diarylmethyl 2,3,4,5,6-pentafluorobenzoate substrates to (IPr)Pd(0) results in the selective cleavage of the O-C(benzyl) bond in part because of a stabilizing η3-interaction between the benzyl ligand and Pd. This is in contrast to previously described Pd-catalyzed Suzuki-Miyaura reactions involving phenyl esters, which involve selective cleavage of the C(acyl)-O bond, because there is no stabilizing η3-interaction. It is anticipated that this fundamental knowledge will aid the development of new catalytic systems, which use esters as electrophiles in cross-coupling reactions.
Synthesis of Triarylmethanes via Palladium-Catalyzed Suzuki Coupling of Trimethylammonium Salts and Arylboronic Acids
Zhang, Zhenming,Wang, Hui,Qiu, Nianli,Kong, Yujing,Zeng, Wenjuan,Zhang, Yongquan,Zhao, Junfeng
, p. 8710 - 8715 (2018/07/21)
An efficient palladium-catalyzed Suzuki coupling of 1,1-diarylmethyl-trimethylammonium triflates with arylboronic acids is reported. This reaction offers a novel approach to triarylmethane derivatives in good to excellent yields with the palladium-catalyzed C-N bond cleavage as the key feature. Broad substrate scope regarding both reaction partners are observed. Moreover, reactive functional groups such as vinyl and formyl groups are conserved in this transformation.
Synthesis of Di- and Triarylmethanes through Palladium-Catalyzed Reductive Coupling of N -Tosylhydrazones and Aryl Bromides
Xia, Yamu,Hu, Fangdong,Xia, Ying,Liu, Zhenxing,Ye, Fei,Zhang, Yan,Wang, Jianbo
, p. 1073 - 1086 (2017/02/24)
A palladium-catalyzed reductive coupling between N-tosylhydrazones and aryl bromides has been developed. The reaction provides an efficient method for the synthesis of diarylmethanes and triarylmethanes via the formation of C(sp2)-C(sp3) single bonds. This new methodology for the synthesis of diarylmethanes and triarylmethanes is featured by the ready availability of the starting materials, mild reaction conditions, and the tolerance of wide range of functional groups. The reaction follows a pathway including palladium carbene formation, migratory insertion, and reduction of the alkylpalladium(II) intermediate.
Benzylation of arenes with benzyl halides synergistically promoted by in situ generated superacid boron trifluoride monohydrate and tetrahaloboric acid
Huang, Ruofeng,Zhang, Xiaohui,Pan, Jing,Li, Jiaqiang,Shen, Hang,Ling, Xuege,Xiong, Yan
supporting information, p. 1540 - 1546 (2015/03/04)
To examine the assembly methodology of diarylmethanes, a benzylation of (hetero)arenes with benzyl halides has been developed and various diarylmethanes were furnished with yields of up to 98% and regioselectivities of up to >99%. The complexation of the by-product halogen hydride with BF3·OEt2 generated the Bronsted acid BF3·HX (HBF3X, X=Cl or Br) in situ to synergistically promote the benzylation.
Palladium-catalyzed diarylmethyl C(sp3)-C(sp2) bond formation: A new coupling approach toward triarylmethanes
Xia, Ying,Hu, Fangdong,Liu, Zhenxing,Qu, Peiyuan,Ge, Rui,Ma, Chen,Zhang, Yan,Wang, Jianbo
, p. 1784 - 1787 (2013/06/26)
Palladium-catalyzed reductive coupling reactions between N-tosylhydrazones and aryl halides lead to the formation of C(sp3)-C(sp2) bonds. This approach provides a general route for the synthesis of triarylmethanes.
Synthesis of enantioenriched triarylmethanes by stereospecific cross-coupling reactions
Taylor, Buck L. H.,Harris, Michael R.,Jarvo, Elizabeth R.
supporting information; experimental part, p. 7790 - 7793 (2012/10/08)
Coupling with inversion: Chiral diarylmethanol derivatives undergo a stereospecific nickel-catalyzed cross-coupling reaction with aryl Grignard reagents (see scheme). The reaction proceeds with inversion of configuration and high enantiospecificity. The m
Palladium-catalyzed C(sp3)-H arylation of diarylmethanes at room temperature: Synthesis of triarylmethanes via deprotonative-cross-coupling processes
Zhang, Jiadi,Bellomo, Ana,Creamer, Andrea D.,Dreher, Spencer D.,Walsh, Patrick J.
supporting information; experimental part, p. 13765 - 13772 (2012/10/08)
Although metal-catalyzed direct arylation reactions of non- or weakly acidic C-H bonds have recently received much attention, chemists have relied heavily on substrates with appropriately placed directing groups to steer reactivity. To date, examples of intermolecular arylation of unactivated C(sp3)-H bonds in the absence of a directing group remain scarce. We report herein the first general, high-yielding, and scalable method for palladium-catalyzed C(sp3)-H arylation of simple diarylmethane derivatives with aryl bromides at room temperature. This method facilitates access to a variety of sterically and electronically diverse hetero- and nonheteroaryl-containing triarylmethanes, a class of compounds with various applications and interesting biological activity. Key to the success of this approach is an in situ metalation of the substrate via C-H deprotonation under catalytic cross-coupling conditions, which is referred to as a deprotonative-cross-coupling process (DCCP). Base and catalyst identification were performed by high-throughput experimentation (HTE) and led to a unique base/catalyst combination [KN(SiMe3)2/Pd-NiXantphos] that proved to efficiently promote the room-temperature DCCP of diarylmethanes. Additionally, the DCCP exhibits remarkable chemoselectivity in the presence of substrates that are known to undergo O-, N-, enolate-, and C(sp2)-H arylation.
Direct arylation/alkylation/magnesiation of benzyl alcohols in the presence of grignard reagents via Ni-, Fe-, or Co-catalyzed sp3 C-O Bond activation
Yu, Da-Gang,Wang, Xin,Zhu, Ru-Yi,Luo, Shuang,Zhang, Xiao-Bo,Wang, Bi-Qin,Wang, Lei,Shi, Zhang-Jie
, p. 14638 - 14641 (2012/11/07)
Direct application of benzyl alcohols (or their magnesium salts) as electrophiles in various reactions with Grignard reagents has been developed via transition metal-catalyzed sp3 C-O bond activation. Ni complex was found to be an efficient catalyst for the first direct cross coupling of benzyl alcohols with aryl/alkyl Grignard reagents, while Fe, Co, or Ni catalysts could promote the unprecedented conversion of benzyl alcohols to benzyl Grignard reagents in the presence of nhexylMgCl. These methods offer straightforward pathways to transform benzyl alcohols into a variety of functionalities.
Tin exchanged heteropoly tungstate: An efficient catalyst for benzylation of arenes with benzyl alcohol
Ramesh Kumar, Ch.,Rao, K.T. Venkateswara,Sai Prasad,Lingaiah
experimental part, p. 17 - 24 (2011/04/21)
The partial exchange of tin with the protons of 12-tungstophosphoric acid (TPA) results in a highly active heterogeneous catalyst for benzylation of arenes with benzyl alcohol as benzylating agent. The catalysts were characterized by X-ray diffraction, Laser-Raman and FT-IR of pyridine adsorption. The catalytic activity depends significantly on the extent of tin exchanged with the protons of heteropoly tungstate. The characterization results suggest the presence of Lewis acidic sites by the exchange of tin. The catalyst with partial exchange of Sn showed high benzylation activity, which in turn related to variation in acidity of the catalysts. The catalyst is highly active for benzylation reaction irrespective of the nature of substituted arenes and benzyl alcohols. These catalysts are highly active compared to other acid catalysts used for benzylation of different arenes. The catalyst is easy to separate from reaction mixture and exhibit consistent activity upon reuse. The plausible reaction mechanism based on the role of both Lewis and Bronsted acid sites of the catalyst was discussed.
PHOTOCHEMICAL REACTIONS OF TRIARYLMETHYL PEROXIDES (II) α- AND β-NAPHTHYLDIPHENYLMETHYL PEROXIDE
Neckers, D. C.,Linden, Shwn-Mei,Taliano, Ross J.,Williams, B. Lee,Zakrzewski, Andrei
, p. 3029 - 3032 (2007/10/02)
The photochemical decomposition of the title compounds and isotopically labeled analogs have been compared to the thermal rections.Rapid radical 1,2-migration and reversible elimination of oxygen from the starting peroxides are indicated.
