1821-23-4Relevant academic research and scientific papers
A NEW RING SYNTHESIS FOR 3- AND POLYSUBSTITUTED FURANS: DIRECTING EFFECTS OF A 3-(ARENESULFONYL) GROUP IN METALATION AND FRIEDEL-CRAFTS PROCESSES
McCombie, S. W.,Shankar, B. B.,Ganguly, A. K.
, p. 4123 - 4126 (1987)
Primary and secondary α-bromoketones react with the potassium salt (3) to afford 2--ketones.On treatment with LDA followed by p-TsOH, good yields of the corresponding 3- or 2,3-substituted-4-tosylfuran are obtained, fro
Nickel-Catalyzed Olefination of Unactivated Aliphatic Dithioacetals
Huang, Li-Fu,Huang, Chih-Hao,Stulgies, Baldur,De Meijere, Armin,Luh, Tien-Yau
, p. 4489 - 4491 (2003)
(Equation presented) Olefination of aliphatic dithioacetals with Grignard reagents is catalyzed by Ni(acac)2 in the presence of an appropriate trialkylphosphine ligand.
Visible-Light Photoredox Catalyzed Dehydrogenative Synthesis of Allylic Carboxylates from Styrenes
Bandini, Marco,Battaglioli, Simone,Liu, Yang,Lombardi, Lorenzo,Menichetti, Arianna,Montalti, Marco,Valenti, Giovanni
, p. 4441 - 4446 (2021/06/28)
The visible-light photoredox/[Co(III)] cocatalyzed dehydrogenative functionalization of cyclic and acyclic styryl derivatives with carboxylic acids is documented. The methodology enables the chemo- and regioselective allylic functionalization of styryl compounds, leading to allylic carboxylates (32 examples) under stoichiometric acceptorless conditions. Intermolecular as well as intramolecular variants are documented in high yields (up to 82%). A mechanistic rationale is also proposed on the basis of a combined experimental and spectroscopic investigation.
Grubbs Metathesis Enabled by a Light-Driven gem-Hydrogenation of Internal Alkynes
Biberger, Tobias,Fürstner, Alois,Zachmann, Raphael J.
, p. 18423 - 18429 (2020/08/25)
[(NHC)(cymene)RuCl2] (NHC=N-heterocyclic carbene) complexes instigate a light-driven gem-hydrogenation of internal alkynes with concomitant formation of discrete Grubbs-type ruthenium carbene species. This unorthodox reactivity mode is harnessed in the form of a “hydrogenative metathesis” reaction, which converts an enyne substrate into a cyclic alkene. The intervention of ruthenium carbenes formed in the actual gem-hydrogenation step was proven by the isolation and crystallographic characterization of a rather unusual representative of this series carrying an unconfined alkyl group on a disubstituted carbene center.
Bimolecular vinylation of arenes by vinyl cations
Bour, Christophe,Gandon, Vincent,Li, Zhilong
supporting information, p. 6507 - 6510 (2020/07/02)
Styrene derivatives can be easily synthesized from vinyl triflates and arenes under mild reaction conditions, using [Li][Al(OC(CF3)3)4] as a catalyst and LiHMDS as a base. This transformation is likely to involve a vinyl cation intermediate as an electrophile, which is corroborated by DFT calculations, deuterium-labeling and other control experiments. The use of an inert weakly coordinating anion is a decisive factor in this bimolecular vinylation process. This journal is
para-Selective arylation and alkenylation of monosubstituted arenes using thianthreneS-oxide as a transient mediator
Chen, Xiao-Yue,Nie, Xiao-Xue,Wu, Yichen,Wang, Peng
, p. 5058 - 5061 (2020/05/18)
Using thianthreneS-oxide (TTSO) as a transient mediator,para-arylation and alkenylation of mono-substituted arenes have been demonstratedviaapara-selective thianthrenation/Pd-catalyzed thio-Suzuki-Miyaura coupling sequence under mild conditions. This reaction features a broad substrate scope, and functional group and heterocycle tolerance. The versatility of this approach was further demonstrated by late-stage functionalization of complex bioactive scaffolds, and direct synthesis of some pharmaceuticals, including Tetriprofen, Ibuprofen, Bifonazole, and LJ570.
Preparation method of para-substituted aryl compound
-
, (2020/06/09)
The invention discloses a preparation method of a para-substituted aryl compound shown as a formula (I) which is described in the specfication. The preparation method is characterized by comprising the following step of: subjecting an aryl sulfonium salt shown as a formula (II) which is described in the specfication and boride to a coupling reaction in a solvent in an inert atmosphere under the action of alkali and a palladium catalyst to obtain the para-substituted aryl compound. According to the method, mono-substituted aromatic hydrocarbon is taken as a substrate, the aryl sulfonium salt isconstructed in situ, and the palladium catalyst catalyzes the aryl sulfonium salt constructed in situ to undergo the Suzuki-Miyaura coupling reaction, so a mono-substituted aromatic hydrocarbon para-arylation or alkenylation product is constructed quickly and efficiently. The method is mild in conditions, high in substrate universality and wide in tolerance of a heterocyclic coupling substrate.
Novel Selective Approach to Terminally Substituted [n]Dendralenes
Polák, Peter,Tobrman, Tomá?
supporting information, p. 957 - 968 (2018/12/11)
Dendralenes are simple alkenes with cross-conjugated double bonds that are frequently synthesized due to being potentially valuable building blocks for the synthesis of more complex structures. The synthetic approaches to dendralenes are based on the cross-coupling reactions of electrophilic and nucleophilic synthons derived from geminally substituted ethylene. Our novel methodology for the synthesis of only terminally substituted [3]- and [4]dendralenes, as well as 2,3-disubstituted buta-1,3-dienes, involves the preparation of 1,2-disubstituted cyclobutenes from readily available 2-bromocyclobutanone and the subsequent thermal ring-opening reactions.
Cyrene as a Bio-Based Solvent for the Suzuki-Miyaura Cross-Coupling
Wilson, Kirsty L.,Murray, Jane,Jamieson, Craig,Watson, Allan J. B.
supporting information, p. 650 - 654 (2017/12/26)
The Suzuki-Miyaura (SM) cross-coupling is the most broadly utilized Pd-catalyzed C-C bond-forming reaction in the chemical industry. A large proportion of SM couplings employ dipolar aprotic solvents; however, current sustainability initiatives and increasingly stringent regulations advocate the use of alternatives that exhibit more desirable properties. Here we describe the scope and utility of the bio-derived solvent Cyrene in SM cross-couplings and evaluate its suitability as a reaction medium for this benchmark transformation from discovery to gram scale.
Iron-Catalyzed Cross-Coupling of Alkenyl Acetates
G?rtner, Dominik,Stein, André Luiz,Grupe, Sabine,Arp, Johannes,Von Wangelin, Axel Jacobi
supporting information, p. 10545 - 10549 (2015/09/02)
Stable C-O linkages are generally unreactive in cross-coupling reactions which mostly employ more electrophilic halides or activated esters (triflates, tosylates). Acetates are cheap and easily accessible electrophiles but have not been used in cross-couplings because the strong C-O bond and high propensity to engage in unwanted acetylation and deprotonation. Reported herein is a selective iron-catalyzed cross-coupling of diverse alkenyl acetates, and it operates under mild reaction conditions (0 C, 2 h) with a ligand-free catalyst (1-2 mol%). Iron clad: Acetates are underutilized electrophiles in metal-catalyzed cross-coupling reactions because of the strong alkenyl C-O bond and their propensity to engage in unwanted reactions. Combination of a ligand-free low-valent Fe catalyst with nucleophilic organomagnesium reagents, low temperature, and short reaction times results in highly selective cross-couplings with alkenyl acetates.
