34979-37-8Relevant academic research and scientific papers
Dirhodium-Catalyzed Enantioselective B?H Bond Insertion of gem-Diaryl Carbenes: Efficient Access to gem-Diarylmethine Boranes
Huang, Ming-Yao,Li, Xiao-Yu,Su, Yu-Xuan,Yang, Liang-Liang,Zhao, Yu-Tao,Zhu, Shou-Fei
supporting information, p. 24214 - 24219 (2021/10/07)
The scarcity of reliable methods for synthesizing chiral gem-diarylmethine borons limits their applications. Herein, we report a method for highly enantioselective dirhodium-catalyzed B?H bond insertion reactions with diaryl diazomethanes as carbene precursors. These reactions afforded chiral gem-diarylmethine borane compounds in high yield (up to 99 % yield), high activity (turnover numbers up to 14 300), high enantioselectivity (up to 99 % ee) and showed unprecedented broad functional group tolerance. The borane compounds synthesized by this method could be efficiently transformed into diaryl methanol, diaryl methyl amine, and triaryl methane derivatives with good stereospecificity. Mechanistic studies suggested that the borane adduct coordinated to the rhodium catalyst and thus interfered with decomposition of the diazomethane, and that insertion of a rhodium carbene (generated from the diaryl diazomethane) into the B?H bond was most likely the rate-determining step.
Halogen-Lithium Exchange of Sensitive (Hetero)aromatic Halides under Barbier Conditions in a Continuous Flow Set-Up
Weidmann, Niels,Nishimura, Rodolfo H. V.,Harenberg, Johannes H.,Knochel, Paul
supporting information, p. 557 - 568 (2020/09/18)
A halogen-lithium exchange reaction of (hetero)aromatic halides performed in the presence of various electrophiles such as aldehydes, ketones, Weinreb amides, and imines using BuLi as exchange reagent and a commercially available flow set-up is reported. The organolithiums generated in situ were instantaneously trapped with various electrophiles (Barbier conditions) resulting in the formation of polyfunctional (hetero)arenes. This method enables the functionalization of (hetero)arenes containing highly sensitive functional groups such as esters, which are not tolerated in batch conditions.
Employing Arynes for the Generation of Aryl Anion Equivalents and Subsequent Reaction with Aldehydes
Gaykar, Rahul N.,Bhunia, Anup,Biju, Akkattu T.
supporting information, p. 11333 - 11340 (2018/07/21)
Arynes are highly reactive intermediates, which are utilized for the electrophilic arylation of various X-H bonds (X = O, N, S etc.). Herein, a new synthetic strategy is demonstrated, where arynes are converted into aryl anion equivalents by treatment with phosphines and a base. The addition of phosphines to arynes form the phosphonium salts, which in the presence of a carbonate base generates the aryl anion equivalent. Subsequent addition of the aryl anions with aldehydes afforded the secondary alcohols.
Kinetic studies on tetrabutylammonium bromochromate oxidation of some mono-and di-substituted benzhydrols
Hemalatha,Asghar, Basim H.,Mansoor, S Sheik
, p. 821 - 826 (2018/03/13)
The oxidation of 12 mono- and di-substituted benzhydrols (BH) by tetrabutylammonium bromochromate (TBABC) have been studied in aqueous acetic acid medium. Absence of any effect of added acrylonitrile on the reaction discounts the possibility of a one-electron oxidation, leading to the formation of free radicals. The tetrabutylammonium bromochromate oxidation of 12 mono- and di-substituted benzhydrols complies with the isokinetic relationship and Hammett relationship. The overall mechanism is proposed to involve a cyclic concerted symmetrical transition state leading to the product.
A general Br?nsted acid-catalyzed allylation of benzhydryl alcohols
Orizu, Ifedi,Bolshan, Yuri
supporting information, p. 5798 - 5800 (2016/12/03)
Efficient Br?nsted acid-catalyzed allylation of benzhydryl alcohols has been developed. The reaction occurs within 5?min in the presence of sub-stoichiometric amounts of HBF4·OEt2to afford the desired products in good to excellent yields. A variety of functional groups were tolerated under the developed conditions including amides, aldehydes, hydroxyl and carboxylic acid.
Br?nsted Acid-Catalyzed Reactions of Trifluoroborate Salts with Benzhydryl Alcohols
Fisher, Kayla M.,Bolshan, Yuri
, p. 12676 - 12685 (2016/01/09)
Br?nsted acid-catalyzed carbon-carbon bond forming methodology using potassium alkynyl- and alkenyltrifluoroborate salts has been developed. Organotrifluoroborates react with benzhydryl alcohols to afford a broad range of alkynes and alkenes in good to excellent yields. This protocol features good atom economy because organotrifluoroborate salts and alcohols react in a 1:1 ratio. Furthermore, a variety of unprotected functional groups were tolerated under the developed conditions, including amide, aldehyde, free hydroxyl, and carboxylic acid.
UV light-mediated difunctionalization of alkenes through aroyl radical addition/1,4-/1,2-Aryl shift cascade reactions
Zheng, Lewei,Huang, Hongli,Yang, Chao,Xia, Wujiong
supporting information, p. 1034 - 1037 (2015/03/30)
UV light-mediated difunctionalization of alkenes through an aroyl radical addition/1,4-/1,2-aryl shift has been described. The resulted aroyl radical from a photocleavage reaction added to acrylamide compounds followed by cyclization led to the formation of oxindoles, whereas the addition to cinnamic amides aroused a unique 1,4-aryl shift reaction. Furthermore, the difunctionalization of alkenes of prop-2-en-1-ols was also achieved through aroyl radical addition and a sequential 1,2-aryl shift cascade reaction.
Fe(OTf)3-catalyzed α-benzylation of aryl methyl ketones with electrophilic secondary and aryl alcohols
Pan, Xiaojuan,Li, Minghao,Gu, Yanlong
supporting information, p. 268 - 274 (2014/01/06)
Acid-catalyzed Friedel-Crafts alkylation of 1,3-dicarbonyl compounds with electrophilic alcohols, is known to be an effective C-C bond forming reaction. However, until now, this reaction has not been amenable for α-alkylation of aryl methyl ketones because of the notoriously low nucleophilicities of these compounds. Therefore, α-alkylation of aryl methyl ketone relies on precious metal catalysts and also, the use of primary alcohols is mandatory. In this study, we found that a system composed of a Fe(OTf)3 catalyst and chlorobenzene solvent is sufficient to promote the title Friedel-Crafts reaction by using benzhydrols as electrophiles. 3,4-Dihydro-9-(2-hydroxy-4,4- dimethyl-6-oxo-1-cyclohexen-1-yl)-3,3-dimethyl-xanthen-1(2 H)-one was also applicable as an electrophile in this type of benzylation reaction. On the basis of this result, a three-component reaction of salicylaldehyde, dimedone, and aryl methyl ketone was also developed, and this provided an efficient way for the synthesis of densely substituted 4H-chromene derivatives. Copyright
A simple procedure for the polymer-supported N-heterocyclic carbene-rhodium complex via click chemistry: A recyclable catalyst for the addition of arylboronic acids to aldehydes
He, Ying,Cai, Chun
supporting information; experimental part, p. 12319 - 12321 (2011/12/15)
A novel polymer-supported carbene-rhodium complex was prepared using a simple procedure via click chemistry. This polymer-supported N-heterocyclic carbene-rhodium complex was characterized and used as a catalyst for the addition of arylboronic acids to aldehydes in good to excellent yields.
Polymer-supported (2,6-dichloro-4-alkoxyphenyl)(2,4-dichlorophenyl) methanol: A new linker for solid-phase organic synthesis
Kurosu, Michio,Biswas, Kallolmay,Crick, Dean C.
, p. 1141 - 1144 (2007/10/03)
(Chemical Equation Presented) An acid and base stable hydroxytetrachlorodiphenylmethyl (HTPM) linker is developed for polymer-supported organic synthesis. The linkers reported here are utilized for loading carboxylic acids, amines, alcohols, and phenols, and are stable to Bronsted and Lewis acids, Bronsted bases, and a wide variety of nucleophiles. However, the HTPM linkers can conveniently be cleaved by the solvolytic displacement reactions with 20% TFA.
