4445-34-5Relevant academic research and scientific papers
Radical Approach to Thioester-Containing Polymers
Smith, Ronald A.,Fu, Guanyao,McAteer, Owen,Xu, Mizhi,Gutekunst, Will R.
, p. 1446 - 1451 (2019)
A new approach to radical ring-opening polymerization is presented that employs a new thionolactone monomer to generate polymers with thioester-containing backbones. The use of a thiocarbonyl acceptor overcomes longstanding reactivity problems in the field to give complete ring-opening and quantitative incorporation into a variety of acrylate polymers. The resulting copolymers readily degrade under hydrolytic conditions, in addition to cysteine-mediated degradation through transthioesterification. The strategy is compatible with reversible addition-fragmentation chain transfer (RAFT) polymerization and permits the synthesis of block polymers for the preparation of well-defined macromolecular structures.
(Cyclopentadienone)iron-Catalyzed Transfer Dehydrogenation of Symmetrical and Unsymmetrical Diols to Lactones
Tang, Yidan,Meador, Rowan I. L.,Malinchak, Casina T.,Harrison, Emily E.,McCaskey, Kimberly A.,Hempel, Melanie C.,Funk, Timothy W.
, p. 1823 - 1834 (2020/02/04)
Air-stable iron carbonyl compounds bearing cyclopentadienone ligands with varying substitution were explored as catalysts in dehydrogenative diol lactonization reactions using acetone as both the solvent and hydrogen acceptor. Two catalysts with trimethylsilyl groups in the 2- A nd 5-positions, [2,5-(SiMe3)2-3,4-(CH2)4(δ4-C4C= O)]Fe(CO)3 (1) and [2,5-(SiMe3)2-3,4-(CH2)3(δ4-C4C= O)]Fe(CO)3 (2), were found to be the most active, with 2 being the most selective in the lactonization of diols containing both primary and secondary alcohols. Lactones containing five-, six-, and seven-membered rings were successfully synthesized, and no over-oxidations to carboxylic acids were detected. The lactonization of unsymmetrical diols containing two primary alcohols occurred with catalyst 1, but selectivity was low based on alcohol electronics and modest based on alcohol sterics. Evidence for a transfer dehydrogenation mechanism was found, and insight into the origin of selectivity in the lactonization of 1°/2° diols was obtained. Additionally, spectroscopic evidence for a trimethylamine-ligated iron species formed in solution during the reaction was discovered.
Regioselective biocatalytic self-sufficient Tishchenko-type reactionviaformal intramolecular hydride transfer
Buljubasic, Isa,Hall, Mélanie,Laggner, Olivia,Merusic, Kemal,Reiter, Tamara,Tassano, Erika,Vogel, Andreas
supporting information, p. 6340 - 6343 (2020/06/21)
A self-sufficient nicotinamide-dependent intramolecular bio-Tishchenko-type reaction was developed. The reaction is catalyzed by alcohol dehydrogenases and proceeds through formal intramolecular hydride transfer on dialdehydes to deliver lactones. Regioselectivity on [1,1′-biphenyl]-2,2′-dicarbaldehyde substrates could be controlledviathe electronic properties of the substituents. Preparative scale synthesis provided access to substituted dibenzo[c,e]oxepin-5(7H)-ones.
Platinum-on-Carbon-Catalyzed Aqueous Oxidative Lactonization of Diols by Using Molecular Oxygen
Ban, Kazuho,Sajiki, Hironao,Sawama, Yoshinari,Takakura, Ryoya
supporting information, p. 1919 - 1923 (2019/09/30)
A lactonization of various diols catalyzed by platinum on carbon (Pt/C) in water under an atmosphere of molecular oxygen was developed. Derivatives of 1,4- 1,5- and 1,6-diols were transformed into the corresponding five-, six-, and seven-membered lactones by the present oxidative lactonization method.
Degradable vinyl copolymers through thiocarbonyl addition-ring-opening (TARO) polymerization
Bingham, Nathaniel M.,Roth, Peter J.
supporting information, p. 55 - 58 (2019/01/03)
The radical copolymerization of the thionolactone dibenzo[c,e]oxepane-5-thione with acrylates, acrylonitrile, and N,N-dimethylacrylamide afforded copolymers containing a controllable amount of backbone thioesters which could be selectively cleaved. The pr
Ruthenium(II) Catalysis/Noncovalent Interaction Synergy for Cross-Dehydrogenative Coupling of Arene Carboxylic Acids
Dana, Suman,Chowdhury, Deepan,Mandal, Anup,Chipem, Francis A. S.,Baidya, Mahiuddin
, p. 10173 - 10179 (2018/11/21)
A ruthenium-catalyzed cross-dehydrogenative coupling is developed with the aid of a weakly coordinating carboxylic acid group toward the dimerization of arene carboxylic acids. The protocol is operationally simple and suitable to fabricate diverse homodimerized as well as cross-dimerized products in high yields. Computational insights have also been unveiled to comprehend the plausible reaction mechanism. The critical innovation of the synthetic strategy hinges on the soluble basic additive DBU, which constitutes a synergy of Ru(II)-catalysis with noncovalent interaction and, thus, stabilizes pivotal intermediates to promote the challenging dimerization process.
A microwave for rapid preparation of biaryl seven-membered lactone method
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Paragraph 0029-0031, (2017/08/10)
The invention provides a method for quickly preparing polyaryls 7-membered lactone in a microwave manner. The method comprises the following steps of A, performing umpolung reaction under microwave irradiation of 700-900 W and at the temperature of 25-80 DEG C by using a compound 1 as a reagent, using dissolved oxygen acetonitrile as solvent and using N-heterocyclic carbene as a catalyst to obtain a crude product; and B, extracting the polyaryls 7-membered lactone, namely a compound 2, from the crude product. An equation of the reaction is as shown in the specification, wherein R and R' are respectively and independently selected from halogen, nitro group, methyl group, methoxy group and phenyl group of which a benzene ring has two common carbon atoms, and X is halogen. By the method, the polyaryls 7-membered lactone with yield higher than 85% can be obtained within 60 minutes at most. Compared with a reported preparation technology, the method has the advantages that reaction time is shortened, production efficiency is high, and a technology is simple.
A microwave-promoted/Assisted method for rapid preparation of biaryl seven-membered lactones
Hu, Chunqi,Li, Jun,Du, Wenting
, p. 301 - 305 (2017/06/05)
Background: Biaryl seven-membered lactones (BSLs), the target compounds are a class of bioactive compounds with anti-Arrhythmic activity, which also serve as a starting material or structural units for chemical synthesis. Objective: To report a simple and efficient procedure for the synthesis of biaryl seven-membered lactones. Method: Under microwave, the umpolung reaction was promoted by N-heterocyclic carbenes under oxygen, with anhydrous potassium carbonate as base and with 1,4,7,10,13,16-Hexanoxacyclooctadecane (18-crown-6) as a phase-Transfer catalyst. Results: The practical protocol was found to be compatible with different structurally diverse substrates and with moderate to excellent yields. Conclusion: This synthesis method has the advantage of high efficacy and novelty, short reaction time, operation simplicity, mild condition and high yields, providing a useful and atom-economic approach to the synthesis of BSLs.
Efficient and Selective Cu/Nitroxyl-Catalyzed Methods for Aerobic Oxidative Lactonization of Diols
Xie, Xiaomin,Stahl, Shannon S.
supporting information, p. 3767 - 3770 (2015/04/14)
Cu/nitroxyl catalysts have been identified that promote highly efficient and selective aerobic oxidative lactonization of diols under mild reaction conditions using ambient air as the oxidant. The chemo- and regioselectivity of the reaction may be tuned by changing the identity of the nitroxyl cocatalyst. A Cu/ABNO catalyst system (ABNO = 9-azabicyclo[3.3.1]nonan-N-oxyl) shows excellent reactivity with symmetrical diols and hindered unsymmetrical diols, whereas a Cu/TEMPO catalyst system (TEMPO = 2,2,6,6-tetramethyl-1-piperidinyl-N-oxyl) displays excellent chemo- and regioselectivity for the oxidation of less hindered unsymmetrical diols. These catalyst systems are compatible with all classes of alcohols (benzylic, allylic, aliphatic), mediate efficient lactonization of 1,4-, 1,5-, and some 1,6-diols, and tolerate diverse functional groups, including alkenes, heterocycles, and other heteroatom-containing groups.
Iron(II) pincer-catalyzed synthesis of lactones and lactams through a versatile dehydrogenative domino sequence
Pea-Lpez, Miguel,Neumann, Helfried,Beller, Matthias
, p. 865 - 871 (2015/03/14)
The synthesis of lactones and lactams by using iron(II) pincer-catalyzed dehydrogenative methodology was developed. Starting from 1,n-diols or 1,n-amino alcohols, this domino transformation takes place through initial dehydrogenation of the substrates, subsequent intramolecular cyclization, and final oxidation to afford the desired products in good yields. The ability to access heterocycles of different sizes makes this protocol especially versatile, in which two consecutive oxidation reactions are performed without requiring an external oxidant. In this paper, we report the application of the Fe-MACHO-BH complex [carbonylhydrido(tetrahydroborato)[bis(2-diisopropylphosphinoethyl)amino]iron(II)] in this atom-efficient and environmentally benign process, for which molecular hydrogen is formed as the only stoichiometric side product. Just a little pinch: The iron(II) pincer-catalyzed synthesis of lactones and lactams from easily available 1,n-diols and 1,n-amino alcohols is explored. The use of a nontoxic metal as well as the generation of molecular hydrogen as the only stoichiometric byproduct makes this method a highly atom-efficient and environmentally benign process.
