22959-34-8Relevant academic research and scientific papers
Multisubstituted pyrazole synthesis via [3?+?2] cycloaddition/rearrangement/N[sbnd]H insertion cascade reaction of α-diazoesters and ynones
Feng, Xiaoming,Liu, Xiaohua,Zeng, Zi,Zhao, Peng
supporting information, p. 132 - 135 (2020/12/21)
The cascade reactions of alkyl α-diazoesters and ynones using Al(OTf)3 as the catalyst are described. A series of 4-substituted pyrazoles were obtained via [3 + 2] cycloaddition, 1,5-ester shift, 1,3-H shift, and N[sbnd]H insertion process. Deuterium labelling experiments, kinetic studies and control experiments were carried out for the rationalization of the mechanism.
Mono-Gold(I)-Catalyzed Enantioselective Intermolecular Reaction of Ynones with Styrenes: Tandem Diels–Alder and Ene Sequence
Nanko, Masaki,Inaba, Yuya,Sekine, Keisuke,Mikami, Koichi
, (2021/02/05)
Gold-catalyzed intermolecular reaction leading to dihydronaphthalene derivatives in one pot from two equivalents of ynones with respect to styrene is uncovered. The [4+2] Diels–Alder cycloaddition of ynones and styrenes is catalyzed by a mono-gold(I) complex and the conjugated acid to provide an unstable 3,8a-dihydronaphthalene to subsequently undergo an intermolecular ene-type reaction with the π-activated ynone to afford multi-component coupling dihydronaphthalene products. Linear relationships between chiral ligand-gold complexes and chiral dihydronaphthalene products proves mono-gold catalysis that triggers an asymmetric tandem Diels–Alder and ene reaction sequence.
Laccase-mediated Oxidations of Propargylic Alcohols. Application in the Deracemization of 1-arylprop-2-yn-1-ols in Combination with Alcohol Dehydrogenases
González-Granda, Sergio,Méndez-Sánchez, Daniel,Lavandera, Iván,Gotor-Fernández, Vicente
, p. 520 - 527 (2019/11/16)
The catalytic system composed by the laccase from Trametes versicolor and the oxy-radical TEMPO has been successfully applied in the sustainable oxidation of fourteen propargylic alcohols. The corresponding propargylic ketones were obtained in most cases in quantitative conversions (87–>99 % yield), demonstrating the efficiency of the chemoenzymatic methodology in comparison with traditional chemical oxidants, which usually lead to problems associated with the formation of by-products. Also, the stereoselective reduction of propargylic ketones was studied using alcohol dehydrogenases such as the one from Ralstonia species overexpressed in E. coli or the commercially available evo-1.1.200, allowing the access to both alcohol enantiomers mostly with complete conversions and variable selectivities depending on the aromatic pattern substitution (97–>99 % ee). To demonstrate the compatibility of the laccase-mediated oxidation and the alcohol dehydrogenase-catalyzed bioreduction, a deracemization strategy starting from the racemic compounds was developed through a sequential one-pot two-step process, obtaining a selection of (S)- or (R)-1-arylprop-2-yn-1-ols with excellent yields (>98 %) and selectivities (>98 % ee) depending on the alcohol dehydrogenase employed.
Covalent Adaptable Networks with Tunable Exchange Rates Based on Reversible Thiol–yne Cross-Linking
Du Prez, Filip E.,Guerre, Marc,Maes, Diederick,Unal, Kamil,Van Herck, Niels,Winne, Johan M.
supporting information, p. 3609 - 3617 (2020/02/04)
The design of covalent adaptable networks (CANs) relies on the ability to trigger the rearrangement of bonds within a polymer network. Simple activated alkynes are now used as versatile reversible cross-linkers for thiols. The click-like thiol–yne cross-linking reaction readily enables network synthesis from polythiols through a double Michael addition with a reversible and tunable second addition step. The resulting thioacetal cross-linking moieties are robust but dynamic linkages. A series of different activated alkynes have been synthesized and systematically probed for their ability to produce dynamic thioacetal linkages, both in kinetic studies of small molecule models, as well as in stress relaxation and creep measurements on thiol–yne-based CANs. The results are further rationalized by DFT calculations, showing that the bond exchange rates can be significantly influenced by the choice of the activated alkyne cross-linker.
Cracking under internal pressure: Photodynamic behavior of vinyl azide crystals through N2release
Shields, Dylan J.,Karothu, Durga Prasad,Sambath, Karthik,Ranaweera, Ranaweera A. A. Upul,Schramm, Stefan,Duncan, Alexander,Duncan, Benjamin,Krause, Jeanette A.,Gudmundsdottir, Anna D.,Naumov, Pan?e
, p. 18565 - 18575 (2020/12/01)
When exposed to UV light, single crystals of the vinyl azides 3- azido-1-phenylpropenone (1a), 3-azido-1-(4-methoxyphenyl)propenone (1b), and 3-azido-1-(4-chlorophenyl)propenone (1c) exhibit dramatic mechanical effects by cracking or bending with the release of N2. Mechanistic studies using laser flash photolysis, supported by quantum mechanical calculations, show that each of the vinyl azides degrades through a vinylnitrene intermediate. However, despite having very similar crystal packing motifs, the three compounds exhibit distinct photomechanical responses in bulk crystals. While the crystals of 1a delaminate and release gaseous N2 indiscriminately under paraffin oil, the crystals of 1b and 1c visibly expand, bend, and fracture, mainly along specific crystallographic faces, before releasing N2. The photochemical analysis suggests that the observed expansion is due to internal pressure exerted by the gaseous product in the crystal lattices of these materials. Lattice energy calculations, supported by nanoindentation experiments, show significant differences in the respective lattice energies. The calculations identify critical features in the crystal structures of 1b and 1c where elastic energy accumulates during gas release, which correspond to the direction of the observed cracks. This study highlights the hitherto untapped potential of photochemical gas release to elicit a photomechanical response and motility of photoreactive molecular crystals.
Gem-Digold Acetylide Complexes for Catalytic Intermolecular [4 + 2] Cycloaddition: Having Two Gold Centers Is Better for Asymmetric Catalysis
Nanko, Masaki,Shibuya, Satoru,Inaba, Yuya,Ono, Soichiro,Ito, Shigekazu,Mikami, Koichi
supporting information, p. 7353 - 7357 (2018/10/15)
Gold(I)-catalyzed highly enantioselective intermolecular [4 + 2] cycloaddition is shown with ynones and cyclohexadiene. Various bicyclo[2.2.2]octadiene derivatives are produced in high yields (up to 99%) with good enantioselectivity (up to 96% ee). Key to the success is generation of the gem-digold terminal alkyne as a catalytic on-cycle species. As proof of the gem-digold catalysis, a positive nonlinear effect is clarified between the ee's of the ligand and the cycloadduct.
2,4,6-TRIALKOXYSTRYL ARYL SULFONES, SULFONAMIDES AND CARBOXAMIDES, AND METHODS OF PREPARATION AND USE
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Page/Page column 58; 59, (2017/02/28)
Compounds according to Formula (I) are provided and salts thereof, wherein R1, R2, R33, R4, R5, R6, R13, A, X and Y are as defined herein. Methods for preparing compounds of Form
Oxidation of propargylic alcohols with a 2-quinoxalinol salen copper(II) complex and tert-butyl hydroperoxide
Weerasiri, Kushan C.,Gorden, Anne E. V.
, p. 1546 - 1550 (2013/04/10)
The copper(II) complex of 2-quinoxalinol salen (salqu) is an efficient catalyst for the selective oxidation of propargylic alcohols to yield the corresponding α,β-acetylenic carbonyl compounds when used in combination with the oxidant tert-butyl hydroperoxide (TBHP). Excellent yields (up to 99 %) are achieved for a variety of propargylic alcohols within 1 h of reaction time. The (salqu)copper(II) complex with TBHP can be used with propargylic alcohols that contain alkyl groups in the α-position, which can be difficult to oxidize selectively with other commonly available methods. By using this catalytic protocol, excellent selectivity was also achieved for the oxidation of propargylic alcohols over that of isolated hydroxy groups, triple bonds, or propargylic methylene groups. The 2-quinoxalinol salen copper(II) complex is an efficient catalyst when used with tert-butyl hydroperoxide for the oxidation of propargylic alcohols to yield the corresponding carbonyl compounds. This catalytic system provides excellent selectivity for the reaction with propargylic alcohols, and high yields (up to 99 %) are achieved within 1 h and with 1 mol-% of catalyst loading. Copyright
Direct synthesis of pyrroles via 1,3-dipolar cycloaddition of azomethine ylides with ynones
Wang, Zheng,Shi, Ying,Luo, Xiaoyan,Han, De-Man,Deng, Wei-Ping
supporting information, p. 1742 - 1745 (2013/06/27)
A direct and facile synthesis of multi-substituted pyrroles via AgOAc-catalyzed 1,3-dipolar cycloaddition of azomethine ylides with ynones is developed, providing the corresponding adducts in moderate to high yields (up to 89%).
Parallel synthesis of "Click" chalcones as antitubulin agents
Utsintong, Maleeruk,Massarotti, Alberto,Caldarelli, Antonio,Theeramunkong, Sewan
, p. 510 - 516 (2013/07/28)
It has been shown that some chalcones are able to inhibit tubulin polymerization, giving cytotoxicity and destruction of tumoral vasculature. A library of 180 novel chalcone analogs has been synthesized via click chemistry and screened for their cytotoxic
