101-49-5Relevant articles and documents
Metal Triflates for the Production of Aromatics from Lignin
Deuss, Peter J.,Lahive, Ciaran W.,Lancefield, Christopher S.,Westwood, Nicholas J.,Kamer, Paul C. J.,Barta, Katalin,de Vries, Johannes G.
, p. 2974 - 2981 (2016)
The depolymerization of lignin into valuable aromatic chemicals is one of the key goals towards establishing economically viable biorefineries. In this contribution we present a simple approach for converting lignin to aromatic monomers in high yields under mild reaction conditions. The methodology relies on the use of catalytic amounts of easy-to-handle metal triflates (M(OTf)x). Initially, we evaluated the reactivity of a broad range of metal triflates using simple lignin model compounds. More advanced lignin model compounds were also used to study the reactivity of different lignin linkages. The product aromatic monomers were either phenolic C2-acetals obtained by stabilization of the aldehyde cleavage products by reaction with ethylene glycol or methyl aromatics obtained by catalytic decarbonylation. Notably, when the method was ultimately tested on lignin, especially Fe(OTf)3 proved very effective and the phenolic C2-acetal products were obtained in an excellent, 19.3±3.2 wt % yield.
Stereoselective Anti-Markovnikov Geminal Diamination and Dioxygenation of Vinylarenes Mediated by the Bromonium Ion
Balaji, Pandur Venkatesan,Chandrasekaran, Srinivasan
, p. 2547 - 2554 (2016)
A straightforward method is reported for the stereoselective anti-Markovnikov geminal diamination and stoichiometric geminal dioxygenation of vinylarenes mediated by a bromonium ion. The role of the substituent on the nucleophile and the nucleophilicity of the heteroatom in the competing geminal and vicinal addition pathways has been described. The stereoselectivity of the geminal dioxygenation is dependent on the ring size of the product and the position of the substituent that induces the stereoselectivity. The migration of the phenyl group through a semi-pinacol rearrangement during the geminal addition process was confirmed by the results of deuterium labelling studies.
Highly efficient and chemoselective interchange of 1,3-oxathioacetals and dithioacetals to acetals promoted by N-halosuccinimide
Karimi, Babak,Seradj, Hassan,Maleki, Jafar
, p. 4513 - 4516 (2002)
Highly efficient interconversion of a range of 1,3-oxathiolanes, 1,3-dithiolanes and 1,3-dithianes to their acetals at ambient temperature using N-bromosuccinimide or N-chlorosuccinimide and different types of alcohols and diols was investigated.
New Br?nsted-Lewis acidic quaternary ammonium ionic liquids: Synthesis, acidity determination and acidity-catalytic activity relationship
Yi, Fengping,Gao, Jie,Zhang, Lirong,Jiang, Xiaoyan
, p. 1260 - 1264 (2015)
A series of new Br?nsted-Lewis acidic ionic liquids, which are operational simplicity, high stability, low cost and applicable for scaling up, have been synthesized and their activity for acetalization was examined. The comprehensive studies on the acidity-catalytic performance relationship of the Br?nsted-Lewis acidic ionic liquids were performed. IR spectroscopy results confirmed that the new Br?nsted-Lewis acidic ionic liquids possess both Br?nsted and Lewis acid sites. The acidities were determined by Hammett method, and further studies on acidity-activity relationship revealed that the acidity played a key role in the acid-catalyzed probe reactions.
Cesium hydroxide catalyzed addition of alcohols and amine derivatives to alkynes and styrene
Tzalis, Dimitrios,Koradin, Christopher,Knochel, Paul
, p. 6193 - 6195 (1999)
In the presence of catalytic amounts of cesium hydroxide (CsOH · H2O), alcohols, substituted anilines and heterocyclic amines undergo an addition in NMP to phenylacetylene leading to functionalized enol ethers and enamines. Anilines add to styrene (90-120°C, 12-14 h) leading to N-substituted anilines in satisfactory yields.
Acetalization of carbonyl compounds catalyzed by acidic ionic liquid immobilized on silica gel
Miao, Jinmei,Wan, Hui,Shao, Yanbing,Guan, Guofeng,Xu, Bin
, p. 77 - 82 (2011)
Imidazolium-silica heterogeneous catalyst (SG-[(CH2) 3SO3H-HIM]HSO4) was prepared by immobilization of acidic ionic liquid 1-(propyl-3-sulfonate) imidazolium hydrosulfate ([(CH2)3SO3H-HIM]HSO4) on silica-gel using tetraethoxysilane (TEOS) as silica source in this study. The properties of the samples were characterized by FT-IR, SEM and TG/DSC. The results suggested that [(CH2)3SO3H-HIM]HSO4 had been successfully immobilized on the surface of silica-gel and the immobilized ionic liquid catalyst SG-[(CH2)3SO 3H-HIM]HSO4 had good thermal stability. The original smooth surface of silica-gel was covered with [(CH2) 3SO3H-HIM]HSO4 and a rough surface of SG-[(CH2)3SO3H-HIM]HSO4 was formed, but the size of particles had no obvious change. Moreover, SG-[(CH 2)3SO3H-HIM]HSO4 exhibited high catalytic activity for a series of acetalization and could be recovered easily. After reused for 10 times in the synthesis of benzaldehyde ethanediol acetal, the catalyst could still give satisfactory catalytic activity.
Sequential Suzuki-Miyaura Coupling/Lewis Acid-Catalyzed Cyclization: An Entry to Functionalized Cycloalkane-Fused Naphthalenes
Mahecha-Mahecha, Camilo,Lecornué, Frédéric,Akinari, Sumita,Charote, Thomas,Gamba-Sánchez, Diego,Ohwada, Tomohiko,Thibaudeau, Sébastien
, p. 6267 - 6271 (2020/09/02)
Functionalized angular cycloalkane-fused naphthalenes were prepared using a two-step process involving a Pd-catalyzed Suzuki-Miyaura coupling of aryl pinacol boronates and vinyl triflates followed by a boron trifluoride etherate-catalyzed cycloaromatization.
Tropylium salts as efficient organic Lewis acid catalysts for acetalization and transacetalization reactions in batch and flow
Lyons,Crocker,Enders,Nguyen
supporting information, p. 3993 - 3996 (2017/09/08)
Acetalization reactions play significant roles in the synthetically important masking chemistry of carbonyl compounds. Herein we demonstrate for the first time that tropylium salts can act as organic Lewis acid catalysts to facilitate acetalization and transacetalization reactions of a wide range of aldehyde substrates. This metal-free method works efficiently in both batch and flow conditions, prompting further future applications of tropylium organocatalysts in green synthesis.
Visible-light-induced acetalization of aldehydes with alcohols
Yi, Hong,Niu, Linbin,Wang, Shengchun,Liu, Tianyi,Singh, Atul K.,Lei, Aiwen
supporting information, p. 122 - 125 (2017/11/27)
In this work, we have achieved a simple and general method for acetalization of aldehydes by means of a photochemical reaction under low-energy visible light irradiation. A broad range of aromatic, heteroaromatic, and aliphatic aldehydes have been protected under neutral conditions in good to excellent yields using a catalytic amount of Eosin Y as the photocatalyst. Our visible light mediated acetalization strategies are successful for more challenging acid-sensitive aldehydes and sterically hindered aldehydes. Notably, this protocol is chemoselective to aldehydes, while ketones remain intact.
Palladium-Catalyzed Aerobic Synthesis of Terminal Acetals from Vinylarenes Assisted by π-Acceptor Ligands
Matsumura, Satoko,Sato, Ruriko,Nakaoka, Sonoe,Yokotani, Wakana,Murakami, Yuka,Kataoka, Yasutaka,Ura, Yasuyuki
, p. 751 - 757 (2017/03/13)
Terminal acetals were synthesized from various vinylarenes and 1,2- or 1,3-diols using a simple PdCl2(MeCN)2/methoxy-p-benzoquinone (MeOBQ)/CuCl catalyst system and 1 atm of O2 under mild reaction conditions by the anti-Markovnikov nucleophilic attack of an oxygen nucleophile on the coordinated vinylarenes. Cyclic α,β-unsaturated carbonyl compounds such as MeOBQ and N-phenylmaleimide were especially effective as additives to afford higher yields of the desired terminal acetals. Kinetic experiments indicated that MeOBQ operates as a π-acceptor ligand for Pd to accelerate the reaction and that the dissociation of a chloride ion from Pd precedes the rate-determining step.
