- Palladium-Catalyzed Direct Dicarbonylation of Amines with Ethylene to Imides
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The selective and effective conversion of low-cost and simple bulk chemicals into high value-added products through catalytic strategy has a wide range of practical significance. Here, a palladium-catalyzed method for the direct and efficient dicarbonylation of amines with basic industrial feedstock ethylene to imide has been developed. Moderate to excellent yields of the desired imides can be produced from readily available amines in a straightforward manner.
- Kuai, Chang-Sheng,Wang, Le-Cheng,Wu, Xiao-Feng,Xu, Jian-Xing
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supporting information
(2022/01/04)
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- New neryl esters from Helichrysum italicum (Roth) G. Don (Asteraceae) essential oil
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Helichrysum italicum (immortelle) is a dwarf aromatic shrub native to the Mediterranean region. The typical subspecies (italicum) produces an essential oil rich in neryl acetate and characteristic β-diketones, italidiones, highly valued in the perfume industry. As esters are an important group of aroma-active volatiles, herein the composition of the ester fraction of this immortelle chemotype essential oil was studied in detail. Chromatographic separation of Corsican immortelle essential oil enabled the discovery of numerous potentially olfactory-interesting esters of nerol and/or angelic acid, undetectable by direct GC-MS analyses of the unfractioned oil. Four esters of nerol and medium-chain branched fatty acids represent new natural products, while several other esters have a rather restricted occurrence in the Plant Kingdom.
- ?or?evi?, Miljana R.,?ivkovi? Sto?i?, Milena Z.,Aksi?, Jelena M.,Gen?i?, Marija S.,Mladenovi?, Marko Z.,Radulovi?, Niko S.
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supporting information
(2020/11/02)
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- Terpene Cyclizations inside a Supramolecular Catalyst: Leaving-Group-Controlled Product Selectivity and Mechanistic Studies
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The tail-to-head terpene cyclization is arguably one of the most complex reactions found in nature. The hydrogen-bond-based resorcinarene capsule represents the first man-made enzyme-like catalyst that is capable of catalyzing this reaction. Based on noncovalent interactions between the capsule and the substrate, the product selectivity can be tuned by using different leaving groups. A detailed mechanistic investigation was performed to elucidate the reaction mechanism. For the cyclization of geranyl acetate, it was found that the cleavage of the leaving group is the rate-determining step. Furthermore, the studies revealed that trace amounts of acid are required as cocatalyst. A series of control experiments demonstrate that a synergistic interplay between the supramolecular capsule and the acid traces is required for catalytic activity.
- Zhang, Qi,Catti, Lorenzo,Pleiss, Jürgen,Tiefenbacher, Konrad
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supporting information
p. 11482 - 11492
(2017/08/30)
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- A clean enzymatic process for producing flavour esters by direct esterification in switchable ionic liquid/solid phases
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A clean biocatalytic approach for producing flavour esters using switchable ionic liquid/solid phases as reaction/separation media has been developed. The phase behaviour of different IL/flavour acetyl ester (geranyl acetate, citronellyl acetate, neryl acetate and isoamyl acetate) mixtures was studied at several concentrations, resulting for all cases in fully homogeneous liquid media at 50 °C, and solid systems at room temperature. By using an iterative centrifugation protocol on the solid IL/flavour ester mixtures at controlled temperatures, the solid IL phase and the liquid flavour ester phase can be easily separated. The excellent suitability of an immobilized Candida antarctica lipase B (Novozym 435) catalyst in the esterification reaction between an aliphatic carboxylic acid (acetic, propionic, butyric or valeric) and a flavour alcohol (isoamyl alcohol, nerol, citronellol or geraniol) in N,N′,N′′,N′′′-hexadecyltrimethyl-ammonium bis(trifluoromethylsulfonyl)imide ([C16tma][NTf2])IL has been demonstrated, the product yield being improved up to 100% under appropriate reaction conditions (enzyme amount, dehydrating molecular sieves, etc.) at 50 °C. The enzymatic synthesis of sixteen different flavour esters was carried out in [C16tma][NTf2] by means of this approach, providing products of up to 0.757 g mL-1 concentration after IL separation. The residual activity of the enzyme/IL system during seven consecutive operation cycles was shown to be practically unchanged after reuse.
- Lozano, Pedro,Bernal, Juana M.,Navarro, Alicia
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p. 3026 - 3033
(2013/01/15)
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- PROCESSES FOR SYNTHESIZING ESTERS BY 1,4-ADDITION OF ALKANOIC ACIDS TO MYRCENE OR ISOPRENE
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Processes are disclosed for synthesizing esters useful in flavorings and fragrances from ?-pinene, myrcene and/or isoprene. The esters can be used in the manufacture of citral, precursors to citral and other products or precursors such as vitamins, nutritional supplements, flavorings, fragrances and other products. The process includes a 1,4-addition of an alkanoic acid to the conjugated diene of myrcene (which can be generated from ?-pinene) or the conjugated diene of isoprene to produce esters thereof.
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Page/Page column 15-16
(2008/06/13)
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- Toward a total synthesis of brassinosteroids; structure assessment of the Ireland-Claisen products of geranyl and neryl esters
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As estimated by 1H NMR analysis, thermal isomerisation of the kinetic silylenolate derived from the ester (Z)-8a proceeds with acceptable diastereo and facial selectivity, thence affording an acid having the required absolute configuration for further elaboration to brassinosteroids.
- Temmem,Uguen,De Cian,Gruber
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p. 3169 - 3173
(2007/10/03)
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- SYNTHESIS OF THE SAN JOSE SCALE'S SEX PHEROMONE COMPONENT USING AN AVAILABLE NATURALLY OCCURRING STARTING MATERIAL
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(Z)-3,7-Dimethyl-2,7-octadien-1-yl propanoate (1), a component of the San Jose scale (Quadraspidiotus perniciosus, Comstock) pheromone, was prepared by the multistage isomerisation of the C6 carbon-carbon double bond of the readily available compound, nerol (3).The synthesis was carried out via the epoxide by subsequent LiAlH4 ring cleavage and Hofmann-like mesylate elimination.
- Novak, Lajos,Poppe, Laszlo,Kis-Tamas, Attila,Szantay, Csaba
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