32271-55-9Relevant academic research and scientific papers
Sequential Two-Step Stereoselective Amination of Allylic Alcohols through the Combination of Laccases and Amine Transaminases
Albarrán-Velo, Jesús,Lavandera, Iván,Gotor-Fernández, Vicente
, p. 200 - 211 (2019/12/03)
A sequential two-step chemoenzymatic methodology for the stereoselective synthesis of (3E)-4-(het)arylbut-3-en-2-amines in a highly selective manner and under mild reaction conditions is described. The approach consists of oxidation of the corresponding racemic alcohol precursors by the use of a catalytic system made up of the laccase from Trametes versicolor and the oxy-radical TEMPO, followed by the asymmetric reductive bio-transamination of the corresponding ketone intermediates. Optimisation of the oxidation reaction, exhaustive amine transaminase screening for the bio-transaminations and the compatibility of the two enzymatic reactions were studied in depth in search of a design of a compatible sequential cascade. This synthetic strategy was successful and the combinations of enzymes displayed a broad substrate scope, with 16 chiral amines being obtained in moderate to good isolated yields (29–75 %) and with excellent enantiomeric excess values (94 to >99 %). Interestingly, both amine enantiomers can be achieved, depending on the selectivity of the amine transaminase employed in the system.
One-pot two-step chemoenzymatic deracemization of allylic alcohols using laccases and alcohol dehydrogenases
Albarrán-Velo, Jesús,Gotor-Fernández, Vicente,Lavandera, Iván
, (2020/07/03)
A series of enantioenriched (hetero)aromatic secondary allylic alcohols has been synthesized through deracemization of the corresponding racemic mixtures combining a non-selective chemoenzymatic oxidation (laccase from Trametes versicolor and oxy-radical TEMPO) and a stereoselective biocatalyzed reduction (lyophilized cells of E. coli overexpressing an alcohol dehydrogenase, ADH). Both steps were performed in aqueous medium under very mild reaction conditions. After optimization, a sequential one-pot two-step protocol was set up, obtaining the corresponding chiral alcohols in moderate to high conversions (48–95%) and enantiomeric excess (65->99% ee). Depending on the ADH stereopreference, both antipodes from these valuable chiral synthons could be prepared, even at preparative scale (119?178 mg), in a straightforward manner.
Silver-catalyzed decarboxylative C(sp2)-C(sp3) coupling reactions: Via a radical mechanism
Fang, Zhongxue,Wei, Chenlong,Lin, Jing,Liu, Zhenhua,Wang, Wei,Xu, Chenshu,Wang, Xuemin,Wang, Yu
supporting information, p. 9974 - 9978 (2017/12/26)
A silver catalyzed decarboxylative C(sp2)-C(sp3) coupling of vinylic carboxylic acids with alcohols, alkylbenzenes, cycloalkanes and cyclic ethers was developed by using DTBP as an oxidant. This reaction tolerates a wide range of substrates, and products are obtained in good to excellent yields. The reaction also shows good stereoselectivity, and only trans-isomers are obtained. In addition, a radical pathway would be involved to facilitate this decarboxylative C(sp2)-C(sp3) coupling reaction.
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.
Multimetallic Ir-Sn3-catalyzed substitution reaction of π-activated alcohols with carbon and heteroatom nucleophiles
Maity, Arnab Kumar,Chatterjee, Paresh Nath,Roy, Sujit
, p. 942 - 956 (2013/07/25)
An atom economic and catalytic substitution reaction of π-activated alcohols by a multimetallic IreSn3 complex has been demonstrated. The multimetallic IreSn3 complex can be easily synthesized from the reaction between [Cp*IrCl2]2 and SnCl2. In presence of as little as 1 mol % of the catalyst three different types of π-activated alcohols, namely benzyl, allyl, and propargyl alcohols, have been successfully transformed into alkylated products using carbon (arenes, heteroarenes, allyltrimethylsilane, and 1,3-dicarbonyls), nitrogen (sulfonamides), oxygen (alcohols), and sulfur (thiols) nucleophiles in very high yields. An electrophilic mechanism is proposed from the Hammett correlation study.
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.
Arenediazonium o-benzenedisulfonimides in Heck-type arylation of allylic alcohols
Barbero, Margherita,Cadamuro, Silvano,Dughera, Stefano
, p. 3443 - 3452 (2008/02/12)
Arenediazonium o-benzenedisulfonimides were reacted with primary and secondary allylic alcohols. The reactions, carried out in aqueous ethanol in the presence of palladium(II) acetate as precatalyst and sodium hydrogen carbonate as base, gave the arylation products with good overall conversion. In all cases, the major products were the β-arylated carbonyl derivatives. The o-benzene-disulfonimide was recovered in high yield from all the reactions, and it was recycled for the preparation of other salts. Georg Thieme Verlag Stuttgart.
A chiral electrophilic selenium reagent to promote the kinetic resolution of racemic allylic alcohols
Tiecco, Marcello,Testaferri, Lorenzo,Santi, Claudio,Tomassini, Cristina,Bonini, Rosaria,Marini, Francesca,Bagnoli, Luana,Temperini, Andrea
, p. 4751 - 4753 (2007/10/03)
(Chemical Equation Presented) The first example of a kinetic resolution process promoted by electrophilic selenium reagents is reported. Racemic allylic alcohols react with half equivalents of a selenenylating agent in methanol leading to the regiospecific formation of the corresponding addition products with a very high level of facial selectivity (from 95:5 to 98:2 dr). The unreacted alcohols can be recovered in an optically enriched form (from 90 to 94% ee).
Tandem Michael-Wittig-Horner reaction: Application to the synthesis of bisabolanes
Chuzel, Olivier,Piva, Olivier
, p. 393 - 402 (2007/10/03)
Bisabolane derivatives have been synthesized from para-substituted cinnamaldehydes according to a tandem Michael - Wittig - Horner reaction. This sequence was applied to a short access to (+/-)-ar-turmerone.
