54396-74-6Relevant academic research and scientific papers
Asymmetric Synthesis of N-Substituted γ-Amino Esters and γ-Lactams Containing α,γ-Stereogenic Centers via a Stereoselective Enzymatic Cascade
Li, Ming,Cui, Yunfeng,Xu, Zefei,Chen, Xi,Feng, Jinhui,Wang, Min,Yao, Peiyuan,Wu, Qiaqing,Zhu, Dunming
supporting information, p. 372 - 379 (2021/10/25)
γ-Amino esters and γ-lactams containing α,γ-stereogenic centers are widely used as chiral intermediates in various bioactive compounds, while their efficient synthesis remains a challenge. Herein, an enzymatic cascade reaction involving an ene reductase (
C-O Bond Activation as a Strategy in Palladium-Catalyzed Cross-Coupling
Becica, Joseph,Leitch, David C.
, p. 641 - 646 (2020/12/14)
The activation of strong C-O bonds in cross-coupling catalysis can open up new oxygenate-based feedstocks and building blocks for complex-molecule synthesis. Although Ni catalysis has been the major focus for cross-coupling of carboxylate-based electrophiles, we recently demonstrated that palladium catalyzes not only difficult C-O oxidative additions but also Suzuki-Type cross-couplings of alkenyl carboxylates under mild conditions. We propose that, depending on the reaction conditions, either a typical Pd(0)/(II) mechanism or a redox-neutral Pd(II)-only mechanism can operate. In the latter pathway, C-C bond formation occurs through carbopalladation of the alkene, and C-O cleavage by β-carboxyl elimination. 1 Introduction 2 A Mechanistic Challenge: Activating Strong C-O Bonds 3 Exploiting Vinylogy for C-Cl and C-O Oxidative Additions 4 An Alternative Mechanism for Efficient Cross-Coupling Catalysis 5 Conclusions and Outlook.
PROCESS FOR PREPARING CARBAMOYLOXYMETHYL TRIAZOLE CYCLOHEXYL ACID COMPOUNDS
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Page/Page column 84-85, (2020/10/27)
Improved methods and intermediates thereof for preparing carbamoyloxy methyl triazole cyclohexyl acid compounds are described. These compounds are useful as LPA antagonists. Formula (I).
Synthetic method for 3-acetoxy-2-cyclohexenyl-1-one and derivatives thereof
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Paragraph 0019; 0021; 0025, (2019/10/01)
The invention discloses a synthetic method for 3-acetoxy-2-cyclohexenyl-1-one and derivatives thereof. The synthetic method comprises the following steps: (1) reacting a substance as described in thespecification with nitromethane at 110 DEG C to obtain a product I as described in the specification, wherein R in the product I is H or CH3; (2) reacting the product I of the step (1) with sodium nitrite and acetic acid at 37 DEG C to obtain a product II as described in the specification; (3) reacting the product II of the step (2) with methanol and concentrated sulfuric acid at 88 DEG C to obtain a product III as described in the specification; and (4) weighing the product III of the step (3), potassium carbonate, palladium on activated carbon and t-butyl hydroperoxide, adding the weighed materials into dichloromethane, carrying out a reaction at 0 DEG C, and allowing temperature to naturally rise to room temperature so as to obtain a product IV, wherein R in the product IV is H or CH3.The synthetic method of the invention is simpler and more efficient, and has high total yield; the toxicity of reagents used in the preparation is smaller than the toxicity of m-methoxybenzoic acid, thionyl chloride and the like used in the prior art; and the method is low in cost, simple and convenient in separation and purification, applicable to large-scale preparation and capable of realizingindustrial mass production. The synthetic method is applicable as a general synthetic method for 3-acetoxy-2-cyclohexenyl-1-one and 4-substituted derivatives thereof.
Scalable and Chemoselective Synthesis of ?-Keto Esters and Acids via Pd-Catalyzed Carbonylation of Cyclic β-Chloro Enones
Kaplan, Justin M.,Hruszkewycz, Damian P.,Strambeanu, Iulia I.,Nunn, Christopher J.,Vangelder, Kelsey F.,Dunn, Anna L.,Wozniak, Derek I.,Dobereiner, Graham E.,Leitch, David C.
, p. 85 - 96 (2018/09/25)
The Pd-catalyzed carbonylation of cyclic β-chloro enones using simple phosphine ligands is described. Screening identified P(Me)(t-Bu)2 as the most general ligand for an array of chloro enone electrophiles. The reaction scope has been evaluated on a milligram scale across 80 examples, with excellent reactivity observed in nearly every case. Carbonylation can be achieved even in the presence of potentially sensitive or inhibitory functional groups, including basic nitrogens as well as aryl chlorides or bromides. Twenty examples have been run on a gram scale, demonstrating scalability and practical utility. Using P(Me)(t-Bu)2, the reaction rate depends on both nucleophile and electrophile identity, with completion times varying between 3 and >18 h under a standard set of conditions. Switching to P(t-Bu)3 for the carbonylation of 3-chlorocyclohex-2-enone with methanol results in a dramatic rate increase, enabling effective catalysis with kinetics consistent with rate-limiting mass transfer. Stoichiometric oxidative addition of 3-chlorocyclohex-2-enone and 3-oxocyclohex-1-enecarbonyl chloride to both Pd[P(t-Bu)3]2 and Pd(PCy3)2 has enabled characterization and isolation of several potential catalytic intermediates, including Pd-vinyl and Pd-acyl species supported by P(t-Bu)3 and PCy3 ligands. Monitoring the oxidative addition of 3-chlorocyclohex-2-enone to Pd(PCy3)2 by NMR spectroscopy indicates that coordination of the alkene precedes oxidative addition. As a result of these studies, methyl 3-oxocyclohex-1-enecarboxylate has been synthesized via Pd-catalyzed carbonylation of 3-chlorocyclohex-2-enone in 90% yield on a 60 g scale with only 0.5 mol % catalyst loading.
Biocatalytic access to nonracemic γ-oxo esters: Via stereoselective reduction using ene-reductases
Turrini, Nikolaus G.,Cioc, Rǎzvan C.,Van Der Niet, Daan J. H.,Ruijter, Eelco,Orru, Romano V. A.,Hall, Mélanie,Faber, Kurt
supporting information, p. 511 - 518 (2017/08/14)
The asymmetric bioreduction of α,β-unsaturated γ-keto esters using ene-reductases from the Old Yellow Enzyme family proceeds with excellent stereoselectivity and high conversion levels, covering a broad range of acyclic and cyclic derivatives. Various strategies were employed to provide access to both enantiomers, which are versatile precursors of bioactive molecules. The regioselectivity of hydride addition on di-activated alkenes was elucidated by isotopic labeling experiments and showed strong preference for the keto moiety as activating/binding group as opposed to the ester. Finally, chemoenzymatic synthesis of (R)-2-(2-oxocyclohexyl)acetic acid was achieved in high ee on a preparative scale combining enzymatic reduction followed by ester hydrogenolysis.
Biocatalytic synthesis of chiral cyclic γ-oxoesters by sequential C-H hydroxylation, alcohol oxidation and alkene reduction
Brenna, Elisabetta,Crotti, Michele,Gatti, Francesco G.,Monti, Daniela,Parmeggiani, Fabio,Pugliese, Andrea,Tentori, Francesca
supporting information, p. 5122 - 5130 (2017/11/09)
A three-step biocatalytic procedure is described for the conversion of methyl and ethyl cyclopentene- and cyclohexenecarboxylates into both the enantiomers of the corresponding chiral 3-oxoesters, which are useful building blocks for the synthesis of active pharmaceutical ingredients. The allylic hydroxylation of the starting cycloalkenecarboxylates is carried out by using R. oryzae resting cells entrapped in alginate beads, in acetate buffer solution at 25 °C. The oxidation of the intermediate allylic alcohols to unsaturated ketones, performed by the laccase/TEMPO system, and the ene-reductase mediated hydrogenation of the alkene bond were carried out in the same reaction vessel in a sequential mode at 30 °C. Being entirely biocatalytic, our multistep procedure provides considerable advantages in terms of selectivity and environmental impact over reported chemical methods.
Exaltone (=Cyclopentadecanone) from Isomuscone (=Cyclohexadecanone), a one-C-atom ring-contraction methodology via a stereospecific favorskii rearrangement: Regioselective application to (-)-(R)-muscone
Chapuis, Christian,Robvieux, Fabrice,Cantatore, Carole,Saint-Leger, Christine,Maggi, Laurent
experimental part, p. 428 - 447 (2012/05/07)
Treatment of cyclohexadecanone (1g; with I2 (2.2 mol-euqiv.) and KOH in MeOH) furnished the unsaturated (Z)-ester 2g in 83% yield, via a stereospecific Favorskii rearrangement (Scheme 1). Further treatment with 3-chloroperbenzoic acid (m-CPBA) afforded the unreported epoxy ester 3g (88% yield), which was cleaved in 33% yield to Exaltone (=cyclopentadecanone; 1f) with NaOH in MeOH/H2O and then HCl at 65°. This methodology was similarly extended to higher (C17) and lower (C15 to C11) cyclic ketone analogues, as well as regioselectively to (-)-(R)-muscone (5c) and homomuscone (5f) (Scheme 2). Olfactive properties of the corresponding macrocyclic 1-oxaspiro[2,n]alkanes and -alkenes 4 and 8, resulting from a Coreyi-Chaykovsky oxiranylation, are also presented. Copyright
Allylic Oxidations Catalyzed by Dirhodium Catalysts under Aqueous Conditions
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Page/Page column 10, (2009/04/24)
The present invention relates to compositions and methods for achieving the efficient allylic oxidation of organic molecules, especially olefins and steroids, under aqueous conditions. The invention concerns the use of dirhodium (II,II) “paddlewheel complexes, and in particular, dirhodium carboximate and tert-butyl hydroperoxide as catalysts for the reaction. The use of aqueous conditions is particularly advantageous in the allylic oxidation of 7-keto steroids, which could not be effectively oxidized using anhydrous methods, and in extending allylic oxidation to enamides and enol ethers.
Asymmetric synthetic access to the hetisine alkaloids: Total synthesis of (+)-nominine
Peese, Kevin M.,Gin, David Y.
supporting information; experimental part, p. 1654 - 1665 (2009/04/04)
A dual cycloaddition strategy for the synthesis of the hetisine alkaloids has been developed, illustrated by a concise asymmetric total synthesis of (+)-nominine (7). The approach relies on an early-stage intramolecular 1,3-dipolar cyclo-addition of a 4-o
