32271-53-7Relevant academic research and scientific papers
Stereodivergent Pd/Cu Catalysis for the Dynamic Kinetic Asymmetric Transformation of Racemic Unsymmetrical 1,3-Disubstituted Allyl Acetates
He, Rui,Huo, Xiaohong,Zhao, Ling,Wang, Feijun,Jiang, Liyin,Liao, Jian,Zhang, Wanbin
supporting information, p. 8097 - 8103 (2020/05/22)
A stereodivergent Pd/Cu catalyst system has been developed for the unprecedented dynamic kinetic asymmetric transformation (DyKAT) of racemic unsymmetrical 1,3-disubstituted allylic acetates with prochiral aldimine esters. A series of α,α-disubstituted α-amino acids bearing vicinal stereocenters were easily prepared with excellent enantioselectivities (up to >99% ee) and diastereoselectivities (up to >20:1 dr). Moreover, all four stereoisomers of the product can be readily obtained simply by switching the configurations of the two chiral metal catalysts. Furthermore, the present work highlights the power of synergistic Pd/Cu catalysis consisting of two common bidentate chiral ligands for stereodivergent synthesis.
Biocatalytic Enantioselective Oxidation of Sec-Allylic Alcohols with Flavin-Dependent Oxidases
Gandomkar, Somayyeh,Jost, Etta,Loidolt, Doris,Swoboda, Alexander,Pickl, Mathias,Elaily, Wael,Daniel, Bastian,Fraaije, Marco W.,Macheroux, Peter,Kroutil, Wolfgang
supporting information, p. 5264 - 5271 (2019/11/13)
The oxidation of allylic alcohols is challenging to perform in a chemo- as well as stereo-selective fashion at the expense of molecular oxygen using conventional chemical protocols. Here, we report the identification of a library of flavin-dependent oxidases including variants of the berberine bridge enzyme (BBE) analogue from Arabidopsis thaliana (AtBBE15) and the 5-(hydroxymethyl)furfural oxidase (HMFO) and its variants (V465T, V465S, V465T/W466H and V367R/W466F) for the enantioselective oxidation of sec-allylic alcohols. While primary and benzylic alcohols as well as certain sugars are well known to be transformed by flavin-dependent oxidases, sec-allylic alcohols have not been studied yet except in a single report. The model substrates investigated were oxidized enantioselectively in a kinetic resolution with an E-value of up to >200. For instance HMFO V465S/T oxidized the (S)-enantiomer of (E)-oct-3-en-2-ol (1 a) and (E)-4-phenylbut-3-en-2-ol with E>200 giving the remaining (R)-alcohol with ee>99% at 50% conversion. The enantioselectivity could be decreased if required by medium engineering by the addition of cosolvents (e. g. dimethyl sulfoxide).
A catalytic allylic cation-induced intermolecular allylation-semipinacol rearrangement
Xu, Ming-Hui,Dai, Kun-Long,Tu, Yong-Qiang,Zhang, Xiao-Ming,Zhang, Fu-Min,Wang, Shao-Hua
, p. 7685 - 7688 (2018/07/15)
A catalytic intermolecular semipinacol rearrangement induced by allylic carbocations has been realized. This tandem reaction is highly efficient under the catalysis of ZnBr2, generating a wide range of α-homoallyl substituted ketones which contain all-carbon quaternary centres in good to excellent yields (up to 98%) with moderate to high diastereoselectivities (up to >20?:?1). Synthetic application of this novel methodology in the construction of core structures of natural products is also reported.
Copper-catalyzed oxidative alkenylation of C(sp3)-H bonds via benzyl or alkyl radical addition to β-nitrostyrenes
Guo, Shengrong,Yuan, Yanqin,Xiang, Jiannan
supporting information, p. 3093 - 3097 (2015/04/14)
A new method for the preparation of (E)-β-alkylstyrene derivatives has been developed via the addition of a benzyl or alkyl radical to β-nitrostyrenes using di-tert-butyl peroxide (DTBP) as the oxidant in the presence of Cu powder catalyst. The C-H bonds in various toluene derivatives, ethers, alkanes and alcohols were successfully converted into C-C bonds to yield the corresponding (E)-β-alkylstyrene derivatives in moderate to good yields.
Chemo-, regio-, and stereoselective Heck-Matsuda arylation of allylic alcohols under mild conditions
Chaudhari, Tohasib Yusub,Hossian, Asik,Manna, Manash Kumar,Jana, Ranjan
supporting information, p. 4841 - 4845 (2015/05/05)
Heck arylation with allylic alcohol is extremely challenging due to chemo-, regio-, and stereoselective scrambling. Here we report a mild protocol for the alcohol selective β- and α-arylation of allylic and cinnamyl alcohols respectively with aryldiazonium salts. The steric and electronic parameters of the alkene play a prominent role in the regioselectivity.
Facile synthesis of Z -alkenes via uphill catalysis
Singh, Kamaljeet,Staig, Shannon J.,Weaver, Jimmie D.
supporting information, p. 5275 - 5278 (2014/05/06)
Catalytic access to thermodynamically less stable Z-alkenes has recently received considerable attention. These approaches have relied upon kinetic control of the reaction to arrive at the thermodynamically less stable geometrical isomer. Herein, we present an orthogonal approach which proceeds via photochemically catalyzed isomerization of the thermodynamic E-alkene to the less stable Z-isomer which occurs via a photochemical pumping mechanism. We consider two potential mechanisms. Importantly, the reaction conditions are mild, tolerant, and operationally simple and will be easily implemented.
Heck-Matsuda reaction of arenediazonium salts in water
Salabert, Jordi,Sebastián, Rosa María,Vallribera, Adelina,Cívicos, José Francisco,Nájera, Carmen
, p. 2655 - 2659 (2013/03/28)
The palladium-catalyzed arylation of alkenes with aryldiazonium salts can be carried out through an environmentally friendly protocol using neat water low palladium loadings at room temperature under base-additive- and ligand-free conditions.
Synthesis and anticancer activity of novel halolactones with β-aryl substituents from simple aromatic aldehydes
G?adkowski, Witold,Skrobiszewski, Andrzej,Mazur, Marcelina,Siepka, Monika,Pawlak, Aleksandra,Obmińska-Mrukowicz, Bozena,Bia?on?ska, Agata,Poradowski, Dominik,Drynda, Angelika,Urbaniak, Mariusz
, p. 10414 - 10423 (2013/11/19)
A series of 20 novel racemic iodo-, bromo- and chlorolactones, possessing β-phenyl-γ-lactone or β-phenyl-δ-lactone framework, were synthesized from commercially available aromatic aldehydes in convenient five-step syntheses. Some of them showed noticeable cytotoxic effect against two cancer lines, Jurkat (human leukaemia) and D17 (canine osteosarcoma). The highest activity, comparable with carboplatin, was observed for cis-5-(1-iodoethyl)-4-(4′-isopropylphenyl)dihydrofuran-2-one against Jurkat cell line.
Allylic activation across an Ir-Sn heterobimetallic catalyst: Nucleophilic substitution and disproportionation of allylic alcohol
Chatterjee, Paresh Nath,Roy, Sujit
supporting information; experimental part, p. 3776 - 3785 (2012/07/14)
A nucleophilic substitution of allylic alcohols with carbon (arene, heteroarene, allyltrimethylsilane, and 1,3-dicarbonyl compound), sulfur (thiol), oxygen (alcohol), and nitrogen (sulfonamide) nucleophiles has been demonstrated using an in house developed [Ir(COD)(SnCl3)l(μ-Cl)]2 heterobimetallic catalyst in 1,2-dichloroethane to afford the corresponding allylic products in moderate to excellent yields. In 4-hydroxycoumarin, allylation occurs at the 3-position. The diaryl-substituted allylic alcohols undergo disproportionation in presence of the heterobimetallic catalyst to provide the corresponding alkenes and chalcones. An electrophilic mechanism is proposed from Hammett correlation study.
Chemoselective conjugate reduction of α,β-unsaturated ketones catalyzed by rhodium amido complexes in aqueous media
Li, Xuefeng,Li, Liangchun,Tang, Yuanfu,Zhong, Ling,Cun, Linfeng,Zhu, Jin,Liao, Jian,Deng, Jingen
supporting information; experimental part, p. 2981 - 2988 (2010/07/05)
Although a notable feature of Noyori's Ru-TsDPEN complex is that the transfer hydrogenation reaction is highly chemoselective for the C-O functional group and tolerant of alkenes, our early report indicated that the chemoselectivity could be switched from C-O to C-C bonds in the transfer hydrogenation of activated α,β-unsaturated ketones. Now we have found that a variety of α,β-unsaturated ketones, even without other electron-withdrawing functional groups, could be reduced on the alkenic double bonds with high selectivities employing amido-rhodium hydride complex in aqueous media, and up to 100% chemoselectivity has been achieved. It is notable that the chemoselectivity was improved significantly on going from organic solvent to water. Moreover, a 1,4-addition mechanism has been proposed on the basis of the corresponding experimental details and computational analysis.
