1008-76-0Relevant articles and documents
Unusual regioselectivity in the opening of epoxides by carboxylic acid enediolates
Domingo, Luis R.,Gil, Salvador,Parra, Margarita,Segura, Jose
, p. 1303 - 1311 (2008)
Addition of carboxylic acid dianions appears to be a potential alternative to the use of aluminium enolates for nucleophilic ring opening of epoxides. These conditions require the use of a sub-stoichiometric amount of amine (10% mol) for dianion generation and the previous activation of the epoxide with LiCl. Yields are good, with high regioselectivity, but the use of styrene oxide led, unexpectedly, to a mixture resulting from the attack on both the primary and secondary carbon atoms. Generally, a low diastereoselectivity is seen on attack at the primary center, however only one diastereoisomer was obtained from attack to the secondary carbon of the styrene oxide.
Direct lactone formation by using hypervalent iodine(III) reagents with KBr via selective C-H abstraction protocol
Dohi, Toshifumi,Takenaga, Naoko,Goto, Akihiro,Maruyama, Akinobu,Kita, Yasuyuki
, p. 3129 - 3132 (2007)
We have developed a new and reliable method for the direct construction of biologically important aryl lactones and phthalides from carboxylic and benzoic acids, using a combination of hypervalent iodine(III) reagents with KBr.
Visible Light-Promoted Magnesium, Iron, and Nickel Catalysis Enabling C(sp3)-H Lactonization of 2-Alkylbenzoic Acids
Li, Sasa,Su, Mincong,Sun, Jie,Hu, Kunjun,Jin, Jian
, p. 5842 - 5847 (2021)
A mild and practical C(sp3)-H lactonization protocol has been achieved by merging photocatalysis and magnesium (iron, nickel) catalysis. A diverse range of 2-alkylbenzoic acids with a variety of substitution patterns could be transformed into the corresponding phthalide products. Based on the mechanistic experimentation and reported prior studies, a possible mechanism for the benzylic oxidative lactonization reaction was proposed with the hypothetic photoactive ternary complex formed between the 2-alkylbenzoic acid substrate, magnesium ion, and bromate anion.
Mechanistic analysis of a copper-catalyzed C-H oxidative cyclization of carboxylic acids
Banerjee, Shibdas,Sathyamoorthi, Shyam,Du Bois,Zare, Richard N.
, p. 7003 - 7008 (2017)
We recently reported that carboxylic acids can be oxidized to lactone products by potassium persulfate and catalytic copper acetate. Here, we unravel the mechanism for this C-H functionalization reaction using desorption electrospray ionization, online electrospray ionization, and tandem mass spectrometry. Our findings suggest that electron transfer from a transient benzylic radical intermediate reduces Cu(ii) to Cu(i), which is then re-oxidized to Cu(ii) in the catalytic cycle. The resulting benzylic carbocation is trapped by the pendant carboxylate group to give the lactone product. Formation of the putative benzylic carbocation is supported by Hammett analysis. The proposed mechanism for this copper-catalyzed oxidative cyclization process differs from earlier reports of analogous reactions, which posit a substrate carboxylate radical as the reactive oxidant.
Gallium-catalyzed reductive lactonization of γ-keto acids with a hydrosilane
Sakai, Norio,Horikawa, Shuhei,Ogiwara, Yohei
, p. 81763 - 81766 (2016)
Described herein is the GaCl3-catalyzed lactonization of γ-keto carboxylic acids in the presence of PhSiH3 leading to the direct preparation of γ-lactone derivatives. This reducing system showed a relatively wide functional group tolerance.
Biocatalytic Asymmetric Reduction of γ-Keto Esters to Access Optically Active γ-Aryl-γ-butyrolactones
??d?o-Dobrowolska, Anna,Borowiecki, Pawe?,Heider, Johann,Kroutil, Wolfgang,Reiter, Tamara,Schühle, Karola,Szaleniec, Maciej,Tataruch, Mateusz,Telatycka, Natalia
, (2020)
An efficient stereoselective syntheses of a series of functionalized optically active γ-aryl-γ-butyrolactones is achieved by enzymatic asymmetric reduction of the corresponding sterically demanding γ-keto esters employing wild-type and recombinant alcohol dehydrogenases. The best stereoselectivities for the reduction via hydrogen transfer was obtained with two short chain dehydrogenases (SDRs) of complementary stereospecificity from Aromatoleum aromaticum, namely the Prelog-specific NADH-dependent (S)-1-phenylethanol dehydrogenase [(S)-PED] and the anti-Prelog-specific (R)-1-(4-hydroxyphenyl)-ethanol dehydrogenase [(R)-HPED], respectively.Biotransformations catalyzed by both enzymes, followed by TFA-catalyzed cyclization of the resulting γ-hydroxy esters, furnished the respective (S)- and (R)-configured products with exquisite optical purity (up to >99% ee). The synthetic value was demonstrated on preparative scale for the asymmetric bioreduction of the model compound, methyl 4-oxo-4-phenylbutanoate, affording optically pure (S)-γ-phenyl-γ-butyrolactone (>99% ee) in 67–74% isolated yield at 89–95% conversion depending on the applied scale. (Figure presented.).
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Price,Tomisek
, p. 2727 (1942)
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γ-Substituted Butyrolactones from Acrolein and Carbonyl Compounds
Barluenga, Jose,Fernandez, Jose R.,Yus, Miguel
, p. 1534 - 1535 (1987)
The lithiation of 3-chloropropanal diethyl acetal (easily prepared from acrolein) at -78 deg C with lithium naphthalenide followed by reaction with various carbonyl compounds, and final oxidation with m-chloroperbenzoic acid leads to γ-susbstituted butyrolactones.
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Oda et al.
, p. 1341 (1961)
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Wolff Rearrangement of Oxidatively Generated α-Oxo Gold Carbenes: An Effective Approach to Silylketenes
Zheng, Yang,Zhang, Junqi,Cheng, Xinpeng,Xu, Xinfang,Zhang, Liming
, p. 5241 - 5245 (2019)
Gold-catalyzed oxidations of alkynes by N-oxides offer direct access to reactive α-oxo gold carbene intermediates from benign and readily available alkynes instead of hazardous diazo carbonyl compounds. Despite various versatile synthetic methods developed based on this strategy, one of the hallmarks of α-oxo carbene/carbenoid chemistry, that is, the Wolff rearrangement, has not been realized in this context. This study discloses the first examples that show the Wolff rearrangement can be readily realized by α-oxo gold carbenes oxidatively generated from TBS-terminated alkynes (TBS=tert-butyldimethylsilyl). The thus-generated silylketenes can be either isolated pure or subsequently trapped by various internal or external nucleophiles in one pot to afford α-silylated carboxylic acids, their derivatives, or TBS-substituted allenes.
Efficient hydrogenation of levulinic acid catalysed by spherical NHC-Ir assemblies with atmospheric pressure of hydrogen
Liu, Yaoqi,Lu, Zeye,Shen, Lingyun,Tu, Tao,Wu, Jiajie,Zheng, Qingshu
, p. 5037 - 5042 (2021)
A practical, efficient, and mild hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL) under 1 atm H2was realized by single-sited 3D porous self-supported N-heterocyclic carbene iridium catalysts. Quantitative yields and selectivities were achieved at 0.02 mol% catalyst loading, and the catalyst could be reused for 9 runs without obvious loss of selectivity or activity.
Hypervalent iodine catalyzed cyclization of aryl-substituted alkanoic acids
Li, Tingting,Xiang, Changbin,Zhang, Bijun,Yan, Jie
, p. 854 - 860 (2014)
A novel and efficient procedure was developed for direct preparation of aryl-substituted lactones from corresponding aryl-substituted alkanoic acids, catalyzed by the in situ generated hypervalent iodine intermediate from iodobenzene (PhI). In this protocol, aryl-substituted alkanoic acids were treated with m-chloroperbenzoic acid (mCPBA) and KBr in the presence of a catalytic amount of PhI in 2,2,2-trifluoroethanol at room temperature for 24 h, resulting in corresponding aryl lactones in moderate-to-good yields. Copyright
Ligand effects in aluminium-catalyzed asymmetric Baeyer-Villiger reactions
Frison, Jean-Cédric,Palazzi, Chiara,Bolm, Carsten
, p. 6700 - 6706 (2006)
Asymmetric Baeyer-Villiger oxidations of racemic and prochiral cyclobutanones can be performed with chiral aluminium-based Lewis acids resulting in products with good enantioselectivities in high yields. By employing substituted BINOL derivatives as ligan
Hydrogenation of Carbonyl Derivatives with a Well-Defined Rhenium Precatalyst
Wei, Duo,Roisnel, Thierry,Darcel, Christophe,Clot, Eric,Sortais, Jean-Baptiste
, p. 80 - 83 (2017)
The first efficient and general rhenium-catalyzed hydrogenation of carbonyl derivatives was developed. The key to the success of the reaction was the use of a well-defined rhenium complex bearing a tridentate diphosphinoamino ligand as the catalyst (0.5 mol %) at 70 °C in the presence of H2 (30 bar). The mechanism of the reaction was investigated by DFT(PBE0-D3) calculations.
Asymmetric Organocatalytic One-Pot, Two-Step Sequential Process to Synthesize Chiral Acetal-Containing Polycyclic Derivatives from Cyclic Hemiacetals and Enones
Liu, Chao,Liu, Yan-Kai
, p. 10450 - 10460 (2017)
We have developed an efficient one-pot, two-step sequential process to synthesize biologically and synthetically important chiral acetal-containing polycyclic derivatives. This novel protocol had been proved to proceed via Michael-lactolization-oxocarbenium ion ring-closing sequence, which was initiated by a key reactive enamine intermediate and interrupted the previously established reaction pathway of two different enones used in this work, and generated the corresponding cycloadducts with excellent stereoselectivity bearing up to seven continuous stereocenters. Both chiral and racemic starting cyclic hemiacetals worked well in this strategy. The synthetic applications of the obtained polycyclic products have also been demonstrated.
Synthesis and chiral recognition of helical poly(phenylacetylene)s bearing L-phenylglycinol and its phenylcarbamates as pendants
Zhang, Chunhong,Wang, Hailun,Yang, Taotao,Ma, Rui,Liu, Lijia,Sakai, Ryosuke,Satoh, Toshifumi,Kakuchi, Toyoji,Okamoto, Yoshio
, p. 809 - 821 (2015)
A series of novel stereoregular one-handed helical poly(phenylacetylene) derivatives (PPA-1 and PPA-1a-g) bearing L-phenylglycinol and its phenylcarbamate residues as pendants was synthesized for use as chiral stationary phases (CSPs) for HPLC, and their chiral recognition abilities were evaluated using 13 racemates. The phenylcarbamate residues include an unsubstituted phenyl, three chloro-substituted phenyls (3-Cl, 4-Cl, 3,5-Cl2), and three methyl-substituted phenyls (3-CH3, 4-CH3, 3,5-(CH3)2). The acidity of the phenylcarbamate N-H proton and the hydrogen bonds formed between the N-H groups of the phenylcarbamate residues were dependent on the type, position, and the number of substituents on the phenylcarbamate residues. The chiral recognition abilities of these polymers significantly depended on the dynamic helical conformation of the main chain with more or less regularly arranged pendants. The chiral recognition abilities seem to be improved by the introduction of substituents on the phenylcarbamate residues, and PPA-1d bearing the more acidic N-H groups due to the 3,5-dichloro substituents, exhibited a higher chiral recognition than the others. PPA-1d showed an efficient chiral recognition for some racemates, and baseline separation was possible for racemates 5, 11, 12, and 15.
Oxidation of Diols with Sodium Bromite Trihydrate in Organic Solvents in the Presence of Alumina
Morimoto, Takashi,Hirano, Masao,Iwasaki, Keiko,Ishikawa, Takashi
, p. 53 - 54 (1994)
The title oxidation of diols with two primary hydroxy groups (symmetrical diols) and those with both a primary and a secondary hydroxy group (unsymmetrical diols) gives the corresponding lactones or the hydroxy ketones, being dependent upon the types of diols.
Efficient Hydrogenation of Biomass Oxoacids to Lactones by Using NHC–Iridium Coordination Polymers as Solid Molecular Catalysts
Liu, Yaoqi,Sun, Zheming,Huang, Changyu,Tu, Tao
, p. 355 - 360 (2017)
A series of NHC–iridium coordination polymers have proven to be robust, efficient and recyclable solid molecular catalysts toward the hydrogenation of biomass levulinic acid (LA) to γ-valerolactone. Along with quantitative yields attained at 0.01 mol % catalyst loading under 50 atm of H2, the solid molecular catalyst was readily recovered and reused for 12 runs without obvious loss of the selectivity and activity. Remarkably, up to 1.2×105 TON, an unprecedented value could be achieved in this important transformation. In addition, a number of LA homologues, analogues and derivatives were well tolerated to deliver various intriguing and functional lactones in good to excellent yields, which further confirmed the feasibility of the solid molecular catalysts.
Aniline-Type Hypervalent Iodine(III) for Intramolecular Cyclization via C?H Bond Abstraction of Hydrocarbons Containing N- and O-Nucleophiles
Nishiguchi, Yuna,Moriyama, Katsuhiko
supporting information, p. 3354 - 3358 (2021/05/17)
We developed a method for the preparation of (diacetoxyiodo)-2-(N-alkylamido)benzene as an aniline-type hypervalent iodine(III). We also achieved direct cyclizations via C?H bond abstraction, such as the Hofmann-L?ffler-Freytag reaction, a direct amination, and a direct lactonization, using the aniline-type hypervalent iodine(III) to obtain corresponding products in high yields. (Figure presented.).