55937-99-0Relevant articles and documents
Diarylmethane compounds as well as preparation method and application thereof
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Paragraph 0139; 0143-0148; 0269-0273, (2019/08/20)
The invention discloses diarylmethane compounds as well as a preparation method and application thereof. The diarylmethane compounds have a molecular structural general formula as defined by a generalformula (I) in the description. The preparation method of the diarylmethane compounds comprises the steps of adding a benzyl halogenated hydrocarbon compound A and an arylboronic acid B into a reaction system containing an organic small-molecular catalyst, an alkali reagent and a solvent, and performing a reaction to prepare the compounds. The diarylmethane compounds provided by the invention contain electron withdrawing groups and an electron-donating group substituted diarylmethane basic structure, and can be widely used for synthesis of pharmaceutical intermediates, particularly polysubstituted methane compounds, and preparation of functional materials; and the preparation method has a simple process and low requirements for reaction conditions, the reaction process is safe and controllable, the atomic utilization rate and production efficiency are high, the regioselectivity and stereoselectivity of the products are efficiently ensured, a frontier science small-molecule organocatalysis concept is introduced, and the method is friendly to the environment.
B(C6F5)3 catalysed reduction of: Para -quinone methides and fuchsones to access unsymmetrical diaryl- and triarylmethanes: Elaboration to beclobrate
Mahesh, Sriram,Vijaya Anand, Ramasamy
, p. 8393 - 8401 (2017/10/19)
A mild and efficient method for the synthesis of unsymmetrical diaryl- and triarylmethanes through a B(C6F5)3 catalyzed reduction of para-quinone methides and fuchsones respectively, using the Hantzsch ester as a reducing source has been developed. Detailed mechanistic investigations revealed that the reaction actually proceeds through a Lewis acid-base pair complex derived from B(C6F5)3 and the Hantzsch ester.
Unsymmetrical diarylmethanes by ferroceniumboronic acid catalyzed direct friedel-crafts reactions with deactivated benzylic alcohols: Enhanced reactivity due to ion-pairing effects
Mo, Xiaobin,Yakiwchuk, Joshua,Dansereau, Julien,Adam McCubbin,Hall, Dennis G.
supporting information, p. 9694 - 9703 (2015/08/18)
The development of general and more atom-economical catalytic processes for Friedel-Crafts alkylations of unactivated arenes is an important objective of interest for the production of pharmaceuticals and commodity chemicals. Ferroceniumboronic acid hexafluoroantimonate salt (1) was identified as a superior air- and moisture-tolerant catalyst for direct Friedel-Crafts alkylations of a variety of slightly activated and neutral arenes with stable and readily available primary and secondary benzylic alcohols. Compared to the use of classical metal-catalyzed alkylations with toxic benzylic halides, this methodology employs exceptionally mild conditions to provide a wide variety of unsymmetrical diarylmethanes and other 1,1-diarylalkane products in high yield with good to high regioselectivity. The optimal method, using the bench-stable ferroceniumboronic acid salt 1 in hexafluoroisopropanol as cosolvent, displays a broader scope compared to previously reported catalysts for similar Friedel-Crafts reactions of benzylic alcohols, including other boronic acids such as 2,3,4,5-tetrafluorophenylboronic acid. The efficacy of the new boronic acid catalyst was confirmed by its ability to activate primary benzylic alcohols functionalized with destabilizing electron-withdrawing groups like halides, carboxyesters, and nitro substituents. Arene benzylation was demonstrated on a gram scale at up to 1 M concentration with catalyst recovery. Mechanistic studies point toward the importance of the ionic nature of the catalyst and suggest that factors other than the Lewis acidity (pKa) of the boronic acid are at play. A SN1 mechanism is proposed where ion exchange within the initial boronate anion affords a more reactive carbocation paired with the non-nucleophilic hexafluoroantimonate counteranion.