1725-03-7Relevant articles and documents
Macrocyclisation of macrodiolide with dimethylaluminium methaneselenolate
Shen, Liu-Lan,Mun, Han-Seo,Jeong, Jin-Hyun
, p. 6895 - 6899 (2010)
Dimethylaluminium methaneselenolate (Me2AlSeMe, 1) acts as an acyl transfer agent for esterification. In cases of direct macrolactonisation (n = 10-12), this selenium-aluminium complex preferentially creates symmetric macrodiolides rather than macrolides. The factors determining macrodilactonisation were investigated and applied toward the total synthesis of norpyrenophorin, which result in a macrodilactonisation yield of 64 %. Dimethylaluminium methaneselenolate (Me2AlSeMe, 1) acts as an acyl transferagent for esterification. In cases of direct macrolactonisation (n = 10-12), this selenium-aluminium complex preferentiallycreates symmetric macrodiolides rather than macrolides. The factors determining macrodilactonisation were investigated and applied toward the total synthesis of nor-pyrenophorine. Copyright
THE FACILE SYNTHESIS OF A LARGE RING LACTONE BY ACID-CATALYSED CYCLISATION OF AN (Z)-ENE-DIYNE HYDROXY ACID PRECURSOR.
Guillerm, Danielle,Linstrumelle, Gerard
, p. 3811 - 3812 (1985)
A large ring lactone is obtained in good yield by acid catalysed cyclisation of the ο-hydroxy acid precursor.
A Polyketide Cyclase That Forms Medium-Ring Lactones
Gao, De-Wei,Jamieson, Cooper S.,Wang, Gaoqian,Yan, Yan,Zhou, Jiahai,Houk,Tang, Yi
, p. 80 - 84 (2021/01/13)
Medium-ring lactones are synthetically challenging due to unfavorable energetics involved in cyclization. We have discovered a thioesterase enzyme DcsB, from the decarestrictine C1 (1) biosynthetic pathway, that efficiently performs medium-ring lactonizations. DcsB shows broad substrate promiscuity toward linear substrates that vary in lengths and substituents, and is a potential biocatalyst for lactonization. X-ray crystal structure and computational analyses provide insights into the molecular basis of catalysis.
Ynamide-Mediated Macrolactonization
Wang, Xuewei,Yang, Ming,Zhao, Junfeng
, p. 5230 - 5235 (2020/05/27)
Macrolactonization represents a long-standing challenge for organic chemists. Herein, an ynamide-mediated macrolactonization of seco-acids with the assistance of an acid catalyst is described. Various macrolactones ranging in ring size from medium to large can be prepared by using this method. The notorious issues associated with conventional macrolactonization reactions, such as the racemization/epimerization of seco-acids containing an α-chirality center, and the E/Z isomerization of α,β-unsaturated seco-acids can be avoided using this method. In addition, the ynamide-mediated two-step macrolactonization reaction can be performed in a one-pot manner, thus offering a user-friendly protocol. Cyclodepsipeptides containing both amide and ester bonds can also be constructed using this method as the key step to facilitate the ring closure. The total synthesis of dehydroxy LI-F04a, which contains a cyclic hexadepsipeptide core, has been accomplished using this method.
Preparation method of 11- andrographolide compound and caprolactone compound (by machine translation)
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Paragraph 0046-0070; 0075-0078, (2019/11/28)
To the method, cyclohexenone spiro-11 - peroxide is used as a raw material, a protic acid is used as a catalyst, fluorine alcohol is used as a solvent, and the reaction temperature is in a range of from 25 °C~60 °C about. The method has the advantages of high yield, low cost, convenience in operation, mild reaction conditions and the like, and is convenient for industrial application. (by machine translation)
Macrolactonization of Alkynyl Alcohol through Rh(I)/Yb(III) Catalysis
Zhang, Wen-Wen,Gao, Tao-Tao,Xu, Li-Jin,Li, Bi-Jie
supporting information, p. 6534 - 6538 (2018/10/20)
A catalytic macrolactonization through oxidative cyclization of alkynyl alcohol by synergistic transition-metal and Lewis-acid catalysis was developed. Because the alkynyl alcohol substrates involved in this method are different from the seco acids that are used in conventional macrolactonization methods, the current method provides a strategically distinct entry to macrolactones. In addition to the operational simplicity, this macrolactonization protocol proceeds at relatively high concentration, precluding the need for high dilution or slow addition procedures.
Polycyclic ketone monooxygenase from the thermophilic fungus Thermothelomyces thermophila: A structurally distinct biocatalyst for bulky substrates
Fürst, Maximilian J.L.J.,Savino, Simone,Dudek, Hanna M.,Castellanos, J. Rúben Gómez,De Souza, Cora Gutiérrez,Rovida, Stefano,Fraaije, Marco W.,Mattevi, Andrea
supporting information, p. 627 - 630 (2017/05/15)
Regio- and stereoselective Baeyer-Villiger oxidations are difficult to achieve by classical chemical means, particularly when large, functionalized molecules are to be converted. Biocatalysis using flavin-containing Baeyer-Villiger monooxygenases (BVMOs) is a wellestablished tool to address these challenges, but known BVMOs have shortcomings in either stability or substrate selectivity. We characterized a novel BVMO from the thermophilic fungus Thermothelomyces thermophila, determined its three-dimensional structure, and demonstrated its use as a promising biocatalyst. This fungal enzyme displays excellent enantioselectivity, acts on various ketones, and is particularly active on polycyclic molecules. Most notably we observed that the enzyme can perform oxidations on both the A and D ring when converting steroids. These functional properties can be linked to unique structural features, which identify enzymes acting on bulky substrates as a distinct subgroup of the BVMO class.
A catalytic oxidation ring 12 alkone method of synthesizing ring twelve lactone
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Paragraph 0018; 0019, (2016/10/07)
The invention discloses a method for synthesizing cyclododecalactone by catalytic oxidation of cyclododecanone. Cyclododecalactone is synthesized by using a molybdenum-containing compound as a catalyst, cyclododecanone as a raw material, a hydrogen dioxide solution as an oxidizing agent and acetonitrile as a solvent, wherein the molybdenum-containing compound is any one selected from ammonium molybdate, sodium molybdate, sodium phosphomolybdate and molybdenum oxide. With the molybdenum-containing compound used as the catalyst, there is no waste acid treatment or strong acid corrosion, energy conservation and emission reduction are realized and safety is high; with cyclododecanone used as the raw material, no high-temperature reflux reaction is required, and economic benefit and environmental benefit are raised; and by applying the hydrogen dioxide solution as an oxidizing agent, cleanability and safety of an industrial preparation reactions are raised, and environmental pollution is reduced.
A highly efficient macrolactonization method via ethoxyvinyl ester
Ohba, Yusuke,Takatsuji, Mayuko,Nakahara, Kenji,Fujioka, Hiromichi,Kita, Yasuyuki
experimental part, p. 3526 - 3537 (2009/12/31)
We present the highly efficient reaction procedure of the macrolactonization method via ethoxyvinyl esters (EVEs). The following procedure was performed: 1)The EVE was prepared from hydroxycarboxylic acid and ethoxyacetylene in the presence of the Ru catalyst [RuCl2(p-cymene)] 2 in acetone; 2) after filtration of the Ru catalyst through a short-neutral SiO2 pad and evaporation of acetone, the EVE formed was diluted in 1,2-dichloroethane (DCE) and the solution was slowly added by a syringe pump to the highly diluted DCE solution of pTsOH (10mol%) at 80°C. Varioussized lactones could be produced by the method described here. It is note worthy that the method can give 9- to 14-membered macrolactones in good yields. This macrolactonization method via EVEs is useful for acid-/base-sensitive substrates. Furthermore, it was found that EVE formation was possible without loosing activity of the Ru catalyst even for the compounds with nucleophilic amine functions. The characteristic feature of the method was exemplified by the reaction of the compound 14 with many functional groups.
Switching from S- to R-selectivity in the Candida antarctica lipase B-catalyzed ring-opening of ω-methylated lactones: Tuning polymerizations by ring size
Van Buijtenen, Jeroen,Van As, Bart A. C.,Verbruggen, Marloes,Roumen, Luc,Vekemans, Jef A. J. M.,Pieterse, Koen,Hilbers, Peter A. J.,Hulshof, Lumbertus A.,Palmans, Anja R. A.,Meijer
, p. 7393 - 7398 (2008/02/08)
Novozym 435-catalyzed ring-opening of a range of ω-methylated lactones demonstrates fascinating differences in rate of reaction and enantioselectivity. A switch from S- to R-selectivity was observed upon going from small (ring sizes ≤7) to large lactones (ring sizes ≥8). This was attributed to the transition from a cisoid to a transoid conformational preference of the ester bond on going from small to large lactones. The S-selectivity of the ring-opening of the small, cisoid lactones was low to moderate, while the R-selectivity of the ring-opening of the large transoid lactones was surprisingly high. The S-selectivity of the ring-opening of the small, cisoid lactones combined with the established R-selectivity of the transesterification of (aliphatic) secondary alcohols prevented polymerization from taking place. Ring-opening of the large, transoid lactones was R-selective with high enantioselectivity. As a result, these lactones could be polymerized, without exception, by straightforward kinetic resolution polymerization, yielding the enantiopure R-polyester with excellent enantiomeric excess (>99%).
