36635-70-8Relevant academic research and scientific papers
Electronically tunable anion-π interactions in pyrylium complexes: Experimental and theoretical studies
Franconetti, Antonio,Contreras-Bernal, Lidia,Jatunov, Sorel,Gomez-Guillen, Manuel,Angulo, Manuel,Prado-Gotor, Rafael,Cabrera-Escribano, Francisca
, p. 18442 - 18453 (2014)
Noncovalent interactions of anions with electron-deficient aromatic rings that have been studied so far involve non-heteroaromatic or nitrogen-based heteroaromatic systems. Here we report the first case of an organic oxygenated aromatic system, in particular the tri-aryl-pyrylium tetrafluoroborate system, for which noncovalent anion-π interactions of the pyrylium cation with the tetrafluoroborate anion have been experimentally detected and demonstrated by means of 19F NMR spectroscopy in solution. A series of pyrylium tetrafluoroborate salts were synthesized in the presence of BF 3·Et2O, by direct reaction of 4-substituted benzaldehydes with 4-substituted acetophenones or via the previously obtained chalcone of the less reactive ketone. Correlations of 19F NMR chemical shifts of tetrafluoroborate anion for most of the synthesized tri-arylpyrylium tetrafluoroborate complexes with both the pyrylium cation molecular weight and the standard substituent Hammett constants, demonstrate anion-π+ interaction to act between the polyatomic anion BF 4- and the pyrylium aromatic system. DFT calculations reveal that an additional (C-H)+-anion hydrogen bond involving the H(5) of pyrylium ring exists for these fluorescent dyes that show a tunable cup-to-cap shape cavity. The strong fluorescence emission observed for some representative pyrylium tetrafluoroborates described herein, makes them a promising class of tunable emission wavelength dyes for laser technology applications. the Partner Organisations 2014.
1-Arylvinyl formats: A New CO Source and Ketone Source in Carbonylative Synthesis of Chalcone Derivatives
Qi, Xinxin,Lai, Ming,Zhu, Min-Jie,Peng, Jin-Bao,Ying, Jun,Wu, Xiao-Feng
, p. 5252 - 5255 (2019/02/25)
1-Arylvinyl formates as a kind of new CO surrogate have been explored for the first time. Most of the known CO precursors usually produce undesired residuals, which have to be removed. In this strategy, after CO release, the in situ generated acetophenones from 1-arylvinyl formates can be successfully applied as a good ketone source in the synthesis of chalcones with benzaldehydes via a palladium-catalyzed reductive carbonylation reaction. A variety of chalcones were isolated in satisfactory to good yields with good substrates compatibilities under mild conditions.
Domino-Fluorination-Protodefluorination Enables Decarboxylative Cross-Coupling of α-Oxocarboxylic Acids with Styrene via Photoredox Catalysis
Zhang, Muliang,Xi, Junwei,Ruzi, Rehanguli,Li, Nan,Wu, Zhongkai,Li, Weipeng,Zhu, Chengjian
, p. 9305 - 9311 (2017/09/25)
Domino-fluorination-protodefluorination decarboxylative cross-coupling of α-keto acids with styrene has been developed via photoredox catalysis. The critical part of this strategy is the formation of the carbon-fluorine (C-F) bond by the capture of a carbon-centered radical intermediate, which will overcome side reactions during the styrene radical functionalization process. Experimental studies have provided evidence indicating a domino-fluorination-protodefluorination pathway with α-keto acid initiating the photoredox cycle. The present catalytic protocol also affords a novel approach for the construction of α,β-unsaturated ketones under mild conditions.
Polyaniline coated on celite, a heterogeneous support for palladium: Applications in catalytic Suzuki and one-pot Suzuki-aldol reactions
Patel, Heta A.,Patel, Arun L.,Bedekar, Ashutosh V.
, p. 8935 - 8945 (2016/10/13)
Particles of celite were coated with polyaniline, characterized and used as a support for heterogenization of palladium metal ions. The prepared heterogeneous palladium catalysts were screened for Suzuki-Miyaura and one-pot Suzuki-aldol reactions with high conversions. The process of heterogenization on celite reduces the PANI consumption ten-fold when anchoring palladium ions onto the support. The recyclable catalyst was also used for the sunlight mediated Suzuki-Miyaura reaction with good conversion.
Transition-Metal-Free Synthesis of Homo- and Hetero-1,2,4-Triaryl Benzenes by an Unexpected Base-Promoted Dearylative Pathway
Rehan, Mohammad,Maity, Sanjay,Morya, Lalit Kumar,Pal, Kaushik,Ghorai, Prasanta
supporting information, p. 7728 - 7732 (2016/07/07)
An unprecedented approach for the synthesis of homo- and hetero-1,2,4-triaryl benzenes has been developed using a simple base-mediated reaction of either α-aryl cinnamyl alcohols or α,γ-di-aryl propanones. The salient feature of this strategy involves the sequential hydride transfer, regiospecific condensation, regiospecific dearylation, and aromatization under metal-free reaction conditions. The synthesis of unsymmetrically substituted triphenylenes by oxidative coupling of the synthesized 1,2,4-triaryl benzenes has also been demonstrated.
