30925-53-2Relevant academic research and scientific papers
SELECTIVE 1,2-ADDITION OF ORGANOCERIUM(III) REAGENTS TO α,β-UNSATURATED CARBONYL COMPOUNDS
Imamoto, Tsuneo,Sugiura, Yasushi
, p. C21 - C23 (1985)
Organocerium(III) reagents react with α,β-unsaturated carbonyl compounds to afford 1,2-addition products in higher regioselectivity in comparison with organolithiums and the Grignard reagents.This selective 1,2-addition of organocerium reagents is considered to proceed through a polar pathway.
Photoredox-Catalyzed Cyclopropanation of Michael Acceptors
del Hoyo, Ana M.,García Suero, Marcos
supporting information, p. 2122 - 2125 (2017/04/24)
A new protocol for the catalytic cyclopropanation of α,β-unsaturated carbonyl compounds with diiodomethane by means of photoredox catalysis has been successfully developed. The transformation is characterized by its mild conditions, functional-group compatibility, and excellent selectivity profile.
Catalyzed Claisen-Schmidt reaction by protonated aluminate mesoporous silica nanomaterial focused on the (E)-chalcone synthesis as a biologically active compound
Sazegar, Mohammad Reza,Mahmoudian, Shaya,Mahmoudi, Ali,Triwahyono, Sugeng,Jalil, Aishah Abdul,Mukti, Rino R.,Nazirah Kamarudin, Nur H.,Ghoreishi, Monir K.
, p. 11023 - 11031 (2016/02/05)
The mesoporous silica structure (MSN) was synthesized using the sol-gel method followed by aluminum grafting and protonation and was then denoted as HAlMSN (Si/Al = 18.9). N2 physisorption confirmed the mesoporous structure with a pore diameter of 3.38 nm. 27Al NMR showed the presence of framework and extra-framework aluminum structures, which led to the formation of strong Lewis and Br?nsted acidic sites. HAlMSN catalyzed the synthesis of (E)-chalcones through the Claisen-Schmidt reaction. Chalcone derivatives have been applied as biologically active compounds with anti-cancer, anti-inflammatory and diuretic pharmacological activities. The products were obtained via reactions on the protonic acid sites of HAlMSN. The significant advantages of this reaction are high yield, easy work up, short reaction time and also compatibility with various organic solvents. The products were obtained in an excellent conversion of 97% at 298 K. The results show that the electron donating substituents exhibit higher conversion in comparison to electron withdrawing substituents. The stability of the catalyst was investigated by reusing it five times for (E)-chalcone production and there was only a slight decrease in its catalytic activity. The highest product of (E)-chalcone was observed with a 1:2 molar ratio of benzaldehyde/acetophenone. A comparative study in chalcone synthesis using the heterogeneous catalysts demonstrated that HAlMSN has a significantly high activity at low temperature.
Siloxyallenes revisited. A useful functional intermediate for the synthesis of (Z)-β-branched Morita-Baylis-Hillman type adducts and (Z)-chalcones
Yoshizawa, Kazuhiro,Shioiri, Takayuki
, p. 6259 - 6286 (2008/02/04)
Siloxyallenes proved to be a useful functional intermediate in the preparation of (Z)-β-branched Morita-Baylis-Hillman type adducts by the reaction of aldehydes with silylacetylenes or siloxypropynes. Various (Z)-chalcones were stereoselectively synthesized from siloxypropynes via siloxyallenes.
Palladium-catalyzed heteroannulation with acetylenic carbinols as synthons-synthesis of quinolines and 2,3-dihydro-4(1H)-quinolones
Mahanty, Jyan S.,De, Mahuya,Das, Palas,Kundu, Nitya G.
, p. 13397 - 13418 (2007/10/03)
o-Iodoanilides 4 reacted with terminal acetylenic carbinols 5 under palladium-catalyzed conditions to yield o-substituted anilides 6. Most of the anilides 6 could be cyclized with NaOEt/EtOH to 2-arylquinolines 2. o-Iodoanilines 7 reacted with carbinols 5 leading to 8 which on palladium(II) assisted cyclisation afforded substituted quinolines 2. An excellent synthesis of the alkaloid dubamine (2n) is reported. Also, the anilides 6 on acid-catalyzed rearrangement, deprotection and cyclisation led to the 2-aryl-2, 3-dihydro-4(1H)-quinolones 16.
Reactions in Strongly Basic Media. Part 10. Base-catylysed Isomerisation of Z- to E-substituted Chalcones
Bowden, Keith,Duah, Christiana K.,Ranson, Richard J.
, p. 109 - 112 (2007/10/02)
The rate coefficients for the methoxide-catalysed isomerisation of substituted (Z)-chalcones have been measured in methanolic dimethyl sulfoxide (DMSO) at 30.0 deg C, as well as for (Z)-chalcone at several temperatures.The reactions are first order in substrate and base.Further, log k1 for the reaction of (Z)-chalcone and (Z)-4-nitrochalcone correlate with an acidity function, Ha, having slopes equal to 0.53 and 0.45, respectively.The effect of substitution has been assessed using the Hammett equation, with ρ equal to 1.99 for the β-phenyl group and 1.93 for the benzoyl group.For the (Z)-chalcone, the enthalpy and entropy of acti vation are 14.2 kcal mol-1 and -14 cal mol-1 K-1, respectively, and the kinetic solvent isotope effect, k2MeOD/k2MeOH, is ca. 2.0.The rate coefficients for the amine-catalysed isomerisation of (Z)-chalcone and (Z)-4-nitrochalcone in DMSO have been measured at 30.0 deg C.The amino bases are a series of secondary aliphatic amines and the Bronstedt coefficients, β, are given as 0.39 and 0.38, respectively.The isomerisation is considered to proceed by rate-determining attack of the base at the β-carbon of the (Z)-chalcone to form a carbanion.The "cis"-conformer of the carbanion then rotates to form the "trans"-conformer, which eliminates the base to give the (E)-chalcone.
Acylcobalt Salophen Reagents. Precursors to Acyl Radical Intermediates for Use in Carbon-to-Carbon Bond-forming Reactions to Alkenes
Coveney, Donal J.,Patel, Vinod F.,Pattenden, Gerald,Thompson, David M.
, p. 2721 - 2729 (2007/10/02)
Acylcobalt salophen reagents (6) are conveniently synthesised from carboxylic acid chlorides following treatment with the sodium derivative (5) produced from reduction of cobalt(II) salophen with sodium amalgam in tetrahydrofuran at room temperature.The acylcobalt salophens (6) undergo homolytic cleavage in the presence of light from a conventional 300 W sunlamp to give acyl radicals (24) which then undergo additions to activated carbon-to-carbon double bonds, leading to enones, viz. (26) , or saturated ketones, viz. (34) .Intramolecular cyclisations of the acylcobalt salophens (42a) and (42b) lead to the ylidenecyclopentanones (43) and (45), respectively.
