- Synthetic method of diarylmethanes
-
The invention discloses a synthetic method of diarylmethanes. The method is characterized in that benzyl pseudohalide and aromatic boric acid are reacted in an organic solvent under alkaline condition. The method employs easily available raw materials, conversion is realized under effect of no transition metal catalysis, water-free and oxygen-free are not required, Lewis acid catalysis is not required, the method has wide substrate universality, and various substituted diarylmethanes can be synthesized by the method.
- -
-
Paragraph 0294; 0295; 0296; 0297; 0298
(2017/08/28)
-
- Coupling of arylboronic acids with benzyl halides or mesylates without adding transition metal catalysts
-
We report herein a transition-metal-free coupling reaction of arylboronic acids with benzyl halides and mesylates for the construction of C(sp2)[sbnd]C(sp3) bonds. A unique feature of this coupling reaction is the formation regioisomers in some cases. Mechanistic studies suggest that this reaction may proceed via an unprecedented Friedel–Crafts-type reaction pathway under base conditions with the assistance of boronic acid moiety.
- Wu, Guojiao,Xu, Shuai,Deng, Yifan,Wu, Chaoqiang,Zhao, Xia,Ji, Wenzhi,Zhang, Yan,Wang, Jianbo
-
p. 8022 - 8030
(2016/11/19)
-
- Synthesis of diarylmethanes through palladium-catalyzed coupling of benzylic phosphates with arylsilanes
-
An efficient approach to the benzylation of arenes has been developed. The reactions described provide straightforward access to diarylmethanes through Pd-catalyzed coupling of benzylic phosphates with arylsilanes in good to excellent yields. The reaction tolerates a wide range of functionalities such as halide, alkoxyl, and nitro groups.
- Zhang, Pengbo,Xu, Jian,Gao, Yuzhen,Li, Xueqin,Tang, Guo,Zhao, Yufen
-
p. 2928 - 2932
(2015/01/16)
-
- Suzuki-miyaura cross-couplings mediated by trans-PdBr(N-Succ)(PPh 3)2: A convenient synthetic method for diarylmethanes and aryl(heteroaryl)- methanes
-
Diarylmethanes can be accessed efficiently by Suzuki-Miyaura cross-couplings of arylboronic acids with benzyl halides mediated by trans-PdBr(N-Succ) (PPh3)2. The methodology can be applied to the synthesis of aryl(heteroaryl)methanes. Georg Thieme Verlag Stuttgart New York.
- Fairlamb, Ian J. S.,Sehnal, Petr,Taylor, Richard J. K.
-
experimental part
p. 508 - 510
(2009/07/11)
-
- N-tosyloxycarbamates as reagents in rhodium-catalyzed C-H amination reactions
-
Metal nitrenes for use in C-H insertion reactions were obtained from N-tosyloxycarbamates in the presence of an inorganic base and a rhodium(II) dimer complex catalyst. The C-H amination reaction proceeds smoothly, and the potassium tosylate that forms as a byproduct is easily removed by filtration or an aqueous workup. This new methodology allows the amination of ethereal, benzylic, tertiary, secondary, and even primary C-H bonds. The intramolecular reaction provides an interesting route to various substituted oxazolidinones, whereas the intermolecular reaction gives trichloroethoxycarbonyl-protected amines that can be isolated with moderate to excellent yields and that cleave easily to produce the corresponding free amine. The development, scope, and limitations of the reactions are discussed herein. Isotopic effects and the electronic nature of the transition state are used to discuss the mechanism of the reaction.
- Huard, Kim,Lebel, Helene
-
supporting information; experimental part
p. 6222 - 6230
(2009/05/27)
-
- One-pot dual substitutions of bromobenzyl chloride, 2-chloromethyl-6- halogenoimidazo[1,2-a]pyridine and -[1,2-b]pyridazine by Suzuki-Miyaura cross-coupling reactions
-
A very simple, mild and inexpensive palladium-catalyzed cross-coupling of (hetero)arylboronic acids with benzylic halides occurs in good yield. This method was successfully expanded to two heterocyclic electrophiles and allowed onepot dual substitutions of bromobenzyl chloride, 2-chloromethyl-6- halogenoimidazo[1,2-a]pyridine or -[1,2-b]pyridazine, leading to numerous new unsymmetrical methylenelinked biaryl systems. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Henry, Nicolas,Enguehard-Gueiffier, Cecile,Thery, Isabelle,Gueiffier, Alain
-
supporting information; experimental part
p. 4824 - 4827
(2009/05/07)
-
- Simple palladium(II) precatalyst for suzuki-miyaura couplings: Efficient reactions of benzylic, aryl, heteroaryl, and vinyl coupling partners
-
trans-PdBr(N-Succ)(PPh3)2 (1) is a universally effective precatalyst for Suzuki-Miyaura cross-couplings of benzylic halides with aryl- or heteroarylboronic acids. Substituted aryl halides and halogenated cyclic enones can be cross-coupled with aryl- or vinylboronic acids in excellent yields. Catalyst recycling is also demonstrated.
- Burns, Michael J.,Fairlamb, Ian J. S.,Kapdi, Anant R.,Sehnal, Petr,Taylor, Richard J. K.
-
p. 5397 - 5400
(2008/09/17)
-
- Suzuki-miyaura cross-coupling reactions of benzyl halides with potassium aryltrifluoroborates
-
(Chemical Equation Presented) The palladium-catalyzed cross-coupling of potassium aryltrifluoroborates with benzylic halides occurs in good yield with high functional group tolerance. The increased stability of potassium aryltrifluoroborates compared to other boron coupling partners makes this an effective route to functionalized methylene-linked biaryl systems.
- Molander, Gary A.,Elia, Maxwell D.
-
p. 9198 - 9202
(2007/10/03)
-
- Air-stable, phosphine-free anionic palladacyclopentadienyl catalysts: Remarkable halide and pseudohalide effects in Stille coupling
-
The Stille cross-coupling of allylic and benzyl bromides is shown to proceed efficiently using phosphine-free dinuclear anionic palladacyclopentadienyl catalysts possessing bridging (N,O)-imidate ligands. The type of bridging anion influences the catalytic activity considerably. Halide anions such as chloride, bromide or iodide also influence the catalytic activity but to a far lesser extent than the pseudohalide imidate anions (from succinimide or phthalimide). A Baldwin-type cooperative effect is seen with 7a using CuI as a co-catalyst, in the presence of two equivalents of CsF in DMF at 40°C. In toluene, these additives slow down substrate turnover. Wiley-VCH Verlag GmbH & Co. KGaA.
- Crawforth, Catherine M.,Fairlamb, Ian J. S.,Kapdi, Anant R.,Serrano, Jose Luis,Taylor, Richard J. K.,Sanchez, Gregorio
-
p. 405 - 412
(2007/10/03)
-
- Suzuki-Miyaura cross-coupling of benzylic phosphates with arylboronic acids
-
(Chemical Equation Presented) Suzuki-Miyaura cross-coupling of benzylic phosphates with arylboronic acids was investigated. Optimum conditions employed the simple catalytic system of palladium(II) acetate (1 mol %) and triphenylphosphine (4 mol %) with either potassium phosphate or potassium carbonate as the base and toluene as the solvent at 90°C. Using the developed conditions, a series of structurally diverse diarylmethanes were prepared.
- McLaughlin, Mark
-
p. 4875 - 4878
(2007/10/03)
-
- Suzuki-miyaura cross-coupling of benzylic carbonates with arylboronic acids
-
(Chemical Equation Presented) The cross-coupling of benzylic carbonates with arylboronic acids gave the corresponding diarylmethanes in high yields by use of the palladium catalyst generated in situ from [Pd(n3-C 3H5)Cl]2 and 1,5-bis(diphenylphosphino)pentane (DPPPent). The Suzuki-Miyaura reaction using DPPPent-palladium catalyst is applicable to syntheses of a broad range of functionalized diarylmethanes.
- Kuwano, Ryoichi,Yokogi, Masashi
-
p. 945 - 947
(2007/10/03)
-
- Palladium-Catalyzed Suzuki - Miyaura Cross-Couplings of Sulfonyl Chlorides and Boronic Acids
-
(Equation presented) Arene-, arylmethane, and alk-2-ene-1-sulfonyl chlorides undergo Suzuki - Miyaura cross-coupling with arene-, heteroarene-, and alkeneboronic acids in THF at reflux. The reactivity order is Arl > ArSO2Cl > ArBr ? ArCl.
- Dubbaka, Srinivas Reddy,Vogel, Pierre
-
-
- Highly active catalyst for the heterogeneous Suzuki-Miyaura reaction: Assembled complex of palladium and non-cross-linked amphiphilic polymer
-
An assembled insoluble catalyst, PdAS, prepared from palladium ((NH 4)2PdCl4 (1)) and non-cross-linked amphiphilic copolymer poly(N-isopropylacrylamide-co-4-diphenylstyrylphosphine) (2) was developed. It was found that PdAS is an excellent catalyst for the Suzuki-Miyaura reaction on three points: (1) The use of 8 × 10 -7 to 5 × 10-4 mol equiv of PdAS afforded the coupling products efficiently after easy workup, with the turnover number reaching up to 1 250 000. (2) The catalyst was reusable many times without loss of catalytic activity. (3) PdAS showed good stability in any reaction medium (i.e., water or aqueous or anhydrous organic solvents). Analytical study of PdAS indicates that the phosphines in 2 coordinate to palladium to form PdCl2(PPh2Ar)2 species.
- Yamada, Yoichi M. A.,Takeda, Koji,Takahashi, Hideyo,Ikegami, Shiro
-
p. 7733 - 7741
(2007/10/03)
-
- Suzuki cross-coupling reaction of benzylic halides with arylboronic acids in the presence of a tetraphosphine/palladium catalyst
-
The cis,cis,cis-1,2,3,4-tetrakis(diphenylphosphinomethyl) cyclopentane-[PdCl(C3H5)]2 system catalyses efficiently the Suzuki cross-coupling reaction of benzylic halides with arylboronic acids. A wide variety of benzylic bromides or chlorides and functionalised arylboronic acids lead selectively to the corresponding diarylmethane adducts in good yields. Furthermore, this catalyst can be used at low loading in many cases.
- Chahen, Ludovic,Doucet, Henri,Santelli, Maurice
-
p. 1668 - 1672
(2007/10/03)
-
- Polyisocyanates of the diphenyl methane series
-
A polyisocyanate or mixture of polyisocyanates in which the main component(s) correspond to the formula: STR1 in which R1, R2, and R3 each represent hydrogen or a saturated alkyl group containing from 1 to 12 carbon atoms, provided that at least two of these radicals represent hydrogen; and m, n, o and p each represent 0 or 1, provided that when m, n, o and/or p represent 0, the free valency is taken up by a hydrogen atom and that the sum of m+n+o+p is greater than 1 on a statistical average. Such polyisocyanate or mixture of polyisocyanates may be produced by first reacting a 4-nitrobenzyl halide, a 3-nitrobenzyl halide, a benzyl halide, a benzyl alcohol or a nitrobenzyl chloride isomer mixture with nitrobenzene, an alkyl-substituted nitrobenzene, an alkyl benzene or benzene in the presence of a Friedel-Crafts or an acid catalyst. This reaction product is then nitrated, the nitro groups are converted to amino groups by reduction or hydrogenation and the amino compound(s) subsequently phosgenated to form the polyisocyanate(s). The purity of the product polyisocyanate may be improved by distilling off secondary products before and/or after the phosgenation.
- -
-
-