50415-85-5Relevant academic research and scientific papers
Catalytic, contra-Thermodynamic Positional Alkene Isomerization
Occhialini, Gino,Palani, Vignesh,Wendlandt, Alison E.
supporting information, p. 145 - 152 (2022/01/19)
The positional isomerization of C═C double bonds is a powerful strategy for the interconversion of alkene regioisomers. However, existing methods provide access to thermodynamically more stable isomers from less stable starting materials. Here, we report
Electrochemical oxidative: Z -selective C(sp2)-H chlorination of acrylamides
Coles, Simon J.,Hareram, Mishra Deepak,Harnedy, James,Morrill, Louis C.,Tizzard, Graham J.
supporting information, p. 12643 - 12646 (2021/12/07)
An electrochemical method for the oxidative Z-selective C(sp2)-H chlorination of acrylamides has been developed. This catalyst and organic oxidant free method is applicable across various substituted tertiary acrylamides, and provides access to a broad range of synthetically useful Z-β-chloroacrylamides in good yields (22 examples, 73% average yield). The orthogonal derivatization of the products was demonstrated through chemoselective transformations and the electrochemical process was performed on gram scale in flow.
Photocatalytic Hydromethylation and Hydroalkylation of Olefins Enabled by Titanium Dioxide Mediated Decarboxylation
Zhu, Qilei,Nocera, Daniel G.
supporting information, p. 17913 - 17918 (2020/12/04)
A versatile method for the hydromethylation and hydroalkylation of alkenes at room temperature is achieved by using the photooxidative redox capacity of the valence band of anatase titanium dioxide (TiO2). Mechanistic studies support a radical-based mechanism involving the photoexcitation of TiO2 with 390 nm light in the presence of acetic acid and other carboxylic acids to generate methyl and alkyl radicals, respectively, without the need for stoichiometric base. This protocol is accepting of a broad scope of alkene and carboxylic acids, including challenging ones that produce highly reactive primary alkyl radicals and those containing functional groups that are susceptible to nucleophilic substitution such as alkyl halides. This methodology highlights the utility of using heterogeneous semiconductor photocatalysts such as TiO2 for promoting challenging organic syntheses that rely on highly reactive intermediates.
Tandem Remote Csp3-H Activation/Csp3-Csp3 Cleavage in Unstrained Aliphatic Chains Assisted by Palladium(II)
Pérez-Gómez, Marta,Azizollahi, Hamid,Franzoni, Ivan,Larin, Egor M.,Lautens, Mark,García-López, José-Antonio
supporting information, p. 973 - 980 (2019/03/04)
We report here a proof-of-concept for the cleavage of unstrained remote Csp3-Csp3 bonds at room temperature assisted by a directing group, opening up new possibilities to use aliphatic carboxylic acids as suitable alkenyl coupling partners. This strategy involves the Pd-mediated Csp3-H activation directed by a tethered 8-aminoquinoline group, followed by a concerted asynchronous carbene insertion into the Pd-C bond, and an unexpected β-carbon-carbon bond splitting. The insertion of a coupling partner into a Pd-C bond is a novel route to promote C-C bond cleavage, which in contrast to most common methodologies does not rely on the use of strained carbocycles.
Enantioselective Hydrogen Atom Transfer: Discovery of Catalytic Promiscuity in Flavin-Dependent 'Ene'-Reductases
Sandoval, Braddock A.,Meichan, Andrew J.,Hyster, Todd K.
supporting information, p. 11313 - 11316 (2017/08/30)
Flavin has long been known to function as a single electron reductant in biological settings, but this reactivity has rarely been observed with flavoproteins used in organic synthesis. Here we describe the discovery of an enantioselective radical dehalogenation pathway for α-bromoesters using flavin-dependent 'ene'-reductases. Mechanistic experiments support the role of flavin hydroquinone as a single electron reductant, flavin semiquinone as the hydrogen atom source, and the enzyme as the source of chirality.
Synthesis of 2-aryloxy butenoates by copper-catalysed allylic C-H carboxylation of allyl aryl ethers with carbon dioxide
Ueno, Atsushi,Takimoto, Masanori,Hou, Zhaomin
, p. 2370 - 2375 (2017/03/20)
Efficient synthesis of 2-aryloxy-3-butenoic acid esters by allylic C-H bond carboxylation of allyl aryl ethers with CO2 has been achieved through deprotonative alumination with an aluminium ate compound (iBu3Al(TMP)Li) followed by NHC-copper-catalysed carboxylation of the resulting aryloxy allylaluminum species. Functional groups such as halogens (F, Cl, Br, I), CF3, amino, methylthio, silyloxy and hetero aromatic groups survived the reaction conditions. The regio- and stereoselective transformation (isomerization) of 2-aryloxy-3-butenoate products to (Z)-2-aryloxy-2-butenate isomers has also been achieved in the presence of a catalytic amount of DBU. These transformations thus constitute an efficient protocol for the divergent synthesis of both 2-aryloxy-3- and 2-butenonates from a single allyl aryl ether substrate using CO2 as a C1 building block.
Highly regio- and stereoselective three-component nickel-catalyzed syn-hydrocarboxylation of alkynes with diethyl zinc and carbon dioxide
Li, Suhua,Yuan, Weiming,Ma, Shengming
supporting information; experimental part, p. 2578 - 2582 (2011/05/03)
Hydrocarboxylation of alkynes: The first example of nickel-catalyzed hydrozincation of alkynes that form stereodefined hydrocarboxylation products is presented (see scheme; cod=cycloocta-1,5-diene). This catalytic system is efficient for the activation of CO2 and the three-component reaction produces products that could be converted into important oxindole or γ-butyrolactam derivatives. Copyright
Mild, efficient, and robust method for stereocomplementary iron-catalyzed cross-coupling using (E)- and (Z)-enol tosylates
Nishikado, Hiroshi,Nakatsuji, Hidefumi,Ueno, Kanako,Nagase, Ryohei,Tanabe, Yoo
experimental part, p. 2087 - 2092 (2010/10/03)
Iron-catalyzed cross-coupling of Grignard reagents (RMgX) with (E)- and (Z)-enol tosylates proceeded smoothly to give a variety of the corresponding (E)- and (Z)-trisubstituted ,-unsaturated methyl esters (total 30 examples; 55-98% yield). The simple, mild, stereoretentive method utilized iron(III) chloride (FeCl3), iron(III) acetylacetonate [Fe(acac)3], and iron(III) tris(dibenzylmethane) [Fe(dbm). The (E)- and (Z)-enol tosylates were readily prepared by the reported stereocomplementary tosylation method from methyl -keto esters or -formyl esters. Methyl -formyl esters were obtained via a practical and robust TiCl4-Et3N-mediated -formylation of methyl esters with methyl formate.
Reactions of diazo compounds with alkenes catalysed by [RuCl(cod)(Cp)]: Effect of the substituents in the formation of cyclopropanation or metathesis products
Basato, Marino,Tubaro, Cristina,Biffis, Andrea,Bonato, Marco,Buscemi, Gabriella,Lighezzolo, Filippo,Lunardi, Pamela,Yianini, Chiara,Benetollo, Franco,Del Zotto, Alessandro
experimental part, p. 1516 - 1526 (2009/09/04)
The reaction of diazo compounds with alkenes catalysed by complex [RuCl(COd)(Cp)] (cod = 1, 5-cyclooctadiene, Cp = cyclopentadienyl) has been studied. The catalytic cycle involves in the first step the decomposition of the diazo derivative to afford the reactive [RuCl(Cp)I=C(R1)R 2)] intermediate and a mechanism is proposed for this step based on a kinetic study of the simple coupling reaction of ethyl diazoacetate. The evolution of the Ru-carbene intermediate in the presence of alkenes depends on the nature of the substituents at both the diazo N2=C(R 1)R2 (R1, R2 = Ph, H; Ph, CO 2Me; Ph, Ph; C(R1)R2 = fluorene) and the olefin substrates R3(H)C= C(H)R4 (R3, R4 = CO2Et, CO2Et; Ph, Ph; Ph, Me; Ph, H; Me, Br; Me, CN; Ph, CN; H, CN; CN, CN). A remarkable reactivity of the complex was recorded, especially towards unstable aryldiazo compounds and electron-poor olefins. The results obtained indicate that either cyclopropanation or metathesis products can be formed: the first products are favoured by the presence of a cyano substituent at the double bond and the second ones by a phenyl.
Palladium(0)-Catalyzed Coupling Reaction of Lithium (α-Carbalkoxyvinyl)cuprates with Organic Halides
Tsuda, Tetsuo,Yoshida, Tsutomu,Saegusa, Takeo
, p. 607 - 610 (2007/10/02)
The palladium(0)-catalyzed coupling reaction of lithium (α-carbalkoxyvinyl)(dicyclohexylamido)cuprates and organic halides such as aryl, vinyl, and benzyl halides was investigated.The lithium (α-carbalkoxyvinyl)dicyclohexylamido)cuprates were generated by conjugate addition of organo(dicyclohexylamido)cuprates to α,β-acetylenic esters.The coupling reaction using a Pd(PPh3)4 catalyst proceeded at room temperature to give synthetically useful α,β-substituted acrylates in good yields.The coupling reaction of the (α-carbalkoxyvinyl)(dicyclohexylamido)cuprate derived from a β-unsubstituted α,β-acetylenic ester took place stereoselectively to give an (E)-α,β-substituted acrylate derivative.In the vinyl halide reaction, the stereochemistry of the vinyl halide component is retained in the coupling product.The use of the dicyclohexylamido group as a nontransferable ligand is important.Thus, in the reaction using an (α-carbalkoxyvinyl)(1-hexynyl)cuprate complex, a nonselective coupling involving the 1-hexynyl group took place.
