20549-48-8Relevant academic research and scientific papers
Heterogeneous Hydroxyl-Directed Hydrogenation: Control of Diastereoselectivity through Bimetallic Surface Composition
Shumski, Alexander J.,Swann, William A.,Escorcia, Nicole J.,Li, Christina W.
, p. 6128 - 6134 (2021/05/29)
Directed hydrogenation, in which product selectivity is dictated by the binding of an ancillary directing group on the substrate to the catalyst, is typically catalyzed by homogeneous Rh and Ir complexes. No heterogeneous catalyst has been able to achieve equivalently high directivity due to a lack of control over substrate binding orientation at the catalyst surface. In this work, we demonstrate that Pd-Cu bimetallic nanoparticles with both Pd and Cu atoms distributed across the surface are capable of high conversion and diastereoselectivity in the hydroxyl-directed hydrogenation reaction of terpinen-4-ol. We postulate that the OH directing group adsorbs to the more oxophilic Cu atom while the olefin and hydrogen bind to adjacent Pd atoms, thus enabling selective delivery of hydrogen to the olefin from the same face as the directing group with a 16:1 diastereomeric ratio.
Dihydridoboranes: Selective Reagents for Hydroboration and Hydrodefluorination
Phillips, Nicholas A.,O'hanlon, James,Hooper, Thomas N.,White, Andrew J. P.,Crimmin, Mark R.
supporting information, p. 7289 - 7293 (2019/10/08)
The preparation of a new series of dihydridoboranes supported by N,N-chelating ligands, [R2NCH2CH2NAr]- (R = alkyl, Ar = aryl), is reported. These new boranes react selectively with carbonyls, imines, and a series of electron-deficient fluoroarenes. The reactivity is complementary to recognized reagents such as pinacolborane, catecholborane, NHC-BH3, and borane (BH3) itself. Selectivities are rationalized by invoking both open- A nd closed-chain forms of the reagents as part of equilibrium mixtures.
From Bugs to Bioplastics: Total (+)-Dihydrocarvide Biosynthesis by Engineered Escherichia coli
Ascue Avalos, Gabriel A.,Toogood, Helen S.,Tait, Shirley,Messiha, Hanan L.,Scrutton, Nigel S.
, p. 785 - 792 (2019/01/29)
The monoterpenoid lactone derivative (+)-dihydrocarvide ((+)-DHCD) can be polymerised to form shape-memory polymers. Synthetic biology routes from simple, inexpensive carbon sources are an attractive, alternative route over chemical synthesis from (R)-carvone. We have demonstrated a proof-of-principle in vivo approach for the complete biosynthesis of (+)-DHCD from glucose in Escherichia coli (6.6 mg L?1). The pathway is based on the Mentha spicata route to (R)-carvone, with the addition of an ′ene′-reductase and Baeyer–Villiger cyclohexanone monooxygenase. Co-expression with a limonene synthesis pathway enzyme enables complete biocatalytic production within one microbial chassis. (+)-DHCD was successfully produced by screening multiple homologues of the pathway genes, combined with expression optimisation by selective promoter and/or ribosomal binding-site screening. This study demonstrates the potential application of synthetic biology approaches in the development of truly sustainable and renewable bioplastic monomers.
Stereodivergent Synthesis of Carveol and Dihydrocarveol through Ketoreductases/Ene-Reductases Catalyzed Asymmetric Reduction
Guo, Jiyang,Zhang, Rui,Ouyang, Jingping,Zhang, Feiting,Qin, Fengyu,Liu, Guigao,Zhang, Wenhe,Li, Hengyu,Ji, Xiaohong,Jia, Xian,Qin, Bin,You, Song
, p. 5496 - 5504 (2018/11/30)
Chiral carveol and dihydrocarveol are important additives in the flavor industry and building blocks in the synthesis of natural products. Despite the remarkable progress in asymmetric catalysis, convenient access to all possible stereoisomers of carveol and dihydrocarveol remains a challenge. Here, we present the stereodivergent synthesis of carveol and dihydrocarveol through ketoreductases/ene-reductases catalyzed asymmetric reduction. By directly asymmetric reduction of (R)- and (S)-carvone using ketoreductases, which have Prelog or anti-Prelog stereopreference, all four possible stereoisomers of carveol with medium to high diastereomeric excesses (up to >99 %) were first observed. Then four stereoisomers of dihydrocarvone were prepared through ene-reductases catalyzed diastereoselective synthesis. Asymmetric reduction of obtained dihydrocarvone isomers by ketoreductases further provide access to all eight stereoisomeric dihydrocarveol with up to 95 % de values. In addition, the absolute configurations of dihydrocarveol stereoisomers were determined by using modified Mosher's method.
Hydrogenation of Carbonyl Derivatives Catalysed by Manganese Complexes Bearing Bidentate Pyridinyl-Phosphine Ligands
Wei, Duo,Bruneau-Voisine, Antoine,Chauvin, Téo,Dorcet, Vincent,Roisnel, Thierry,Valyaev, Dmitry A.,Lugan, No?l,Sortais, Jean-Baptiste
supporting information, p. 676 - 681 (2017/12/26)
Manganese(I) catalysts incorporating readily available bidentate 2-aminopyridinyl-phosphine ligands achieve a high efficiency in the hydrogenation of carbonyl compounds, significantly better than parent ones based on more elaborated and expensive tridentate 2,6-(diaminopyridinyl)-diphosphine ligands. The reaction proceeds with low catalyst loading (0.5 mol%) under mild conditions (50 °C) with yields up to 96%. (Figure presented.).
Production of flavours and fragrances via bioreduction of (4R)-(-)-carvone and (1R)-(-)-myrtenal by non-conventional yeast whole-cells
Goretti, Marta,Turchetti, Benedetta,Cramarossa, Maria Rita,Forti, Luca,Buzzini, Pietro
, p. 5736 - 5748 (2013/07/19)
As part of a program aiming at the selection of yeast strains which might be of interest as sources of natural flavours and fragrances, the bioreduction of (4R)-(-)-carvone and (1R)-(-)-myrtenal by whole-cells of non-conventional yeasts (NCYs) belonging to the genera Candida, Cryptococcus, Debaryomyces, Hanseniaspora, Kazachstania, Kluyveromyces, Lindnera, Nakaseomyces, Vanderwaltozyma and Wickerhamomyces was studied. Volatiles produced were sampled by means of headspace solid-phase microextraction (SPME) and the compounds were analysed and identified by gas chromatography-mass spectroscopy (GC-MS). Yields (expressed as % of biotransformation) varied in dependence of the strain. The reduction of both (4R)-(-)-carvone and (1R)-(-)-myrtenal were catalyzed by some ene-reductases (ERs) and/or carbonyl reductases (CRs), which determined the formation of (1R,4R)-dihydrocarvone and (1R)-myrtenol respectively, as main flavouring products. The potential of NCYs as novel whole-cell biocatalysts for selective biotransformation of electron-poor alkenes for producing flavours and fragrances of industrial interest is discussed.
Synthesis of optically active dihydrocarveol via a stepwise or one-pot enzymatic reduction of (R)- and (S)-carvone
Chen, Xi,Gao, Xiuzhen,Wu, Qiaqing,Zhu, Dunming
experimental part, p. 734 - 738 (2012/08/29)
A recombinant enoate reductase LacER from Lactobacillus casei catalyzed the reduction of (R)-carvone and (S)-carvone to give (2R,5R)-dihydrocarvone and (2R,5S)-dihydrocarvone with 99% and 86% de, respectively, which were further reduced to dihydrocarveols by a carbonyl reductase from Sporobolomyces salmonicolor SSCR or Candida magnolia CMCR. For (R)-carvone, (1S,2R,5R)-dihydrocarveol was produced as the sole product with >99% conversion, while (1S,2R,5S)-dihydrocarveol was obtained as the major product, but with a lower de when (S)-carvone was used as the substrate. The one-pot reduction was performed at a 0.1 M substrate concentration, indicating that it might provide an effective synthetic route to this type of chiral compound.
Asymmetric reduction of (4R)-(-)-carvone catalyzed by Baker's yeast in aqueous mono- and biphasic systems
Silva, Vanessa Dutra,Stambuk, Boris Ugarte,Nascimento, Maria Da Graa
experimental part, p. 98 - 104 (2012/06/30)
(1R,4R)-dihydrocarvone (2), an important renewable building block, was prepared with good conversions and excellent diastereoisomeric excess through the reduction of the α,β-unsatured carbon-carbon double bond of (4R)-(-)-carvone (1) mediated by Baker's yeast (BY) in aqueous mono- and biphasic systems. Some parameters that may alter this bioreduction reaction, such as the concentrations of yeast and substrate, temperature, and pH, were evaluated. The effect of the addition of different additives on the course of 1 biotransformation was also investigated. The results showed that the conversion and diastereoisomeric excesses were strongly dependent on these variables. The optimum reaction conditions were 100 g L-1 of BY, 16.6 mM of substrate, and pH 7.5 at 26 °C in the presence of DMSO, trehalose, or sucrose as additives. Under the optimum conditions, the (1R,4R)-dihydrocarvone was recovered with diastereoisomeric excesses of 92-99% and with conversions of 70-74%.
Diplogelasinospora grovesii IMI 171018, a new whole cell biocatalyst for the stereoselective reduction of ketones
Carballeira, Jose D.,Alvarez, Emilio,Campillo, Mercedes,Pardo, Leonardo,Sinisterra, Jose V.
, p. 951 - 962 (2007/10/03)
A screening of 416 strains (71 bacterial strains, 45 actinomycetes, 59 yeast, 60 basidiomycetes, 33 marine fungi and 148 filamentous fungi) has been performed to look for microorganisms that display reductase activity in the absence of oxidase activity. A new microorganism, Diplogelasinospora grovesii IMI 171018 (a nonpathogen strain), was isolated and showed very high activity and stereoselectivity in the reduction of cyclic ketones. The fungus was selected due to its selectivity towards monocyclic and bicyclic ketones and its easy culture conditions, which allow an easy scale-up. D. grovesii is more active in the reduction of conventional ketones than S. cerevisiae type II (from Sigma) and can work in the presence of high ketone concentrations (2 = 0.549) and can be used to explain and to predict the structure of ketones that can or cannot be reduced by this microorganism.
Binreduction of (R)-carvone and regioselective baeyer-villiger oxidations: Application to the asymmetric synthesis of cryptophycin fragment A
Varie, David L.,Brennan, John,Briggs, Barbara,Cronin, Jason S.,Hay, David A.,Rieck III, John A.,Zmijewski, Milton J.
, p. 8405 - 8408 (2007/10/03)
Cryptophycin fragment A (1) was prepared in high enantiomeric purity in 10 steps from (R)-carvone. A stereoselective bioreduction of (R)-carvone to neodihydrocarveol and a regioselective Baeyer-Villiger oxidation of cyclohexanone 8 with pertrifluoroacetic acid were employed in this synthesis.
