627-58-7Relevant academic research and scientific papers
Selective enzymatic epoxidation of dienes: Generation of functional enantiomerically enriched diene monoepoxy monomers
Hu, Shanghui,Gupta, Pankaj,Prasad, Ashok K,Gross, Richard A,Parmar, Virinder S
, p. 6763 - 6766 (2002)
Enantiomerically enriched diene monoepoxides were selectively synthesized using oxidases from Pseudomonas sp. and chloroperoxidase from Caldariomyces fumago. These monoepoxides are useful monomers for generating functional chiral polymeric materials.
Total Syntheses of (±)-Isosteviol and (±)-Beyer-15-ene-3β,19-diol by Manganese(III)-Based Oxidative Quadruple Free-Radical Cyclization
Snider, Barry B.,Kiselgof, Jane Y.,Foxman, Bruce M.
, p. 7945 - 7952 (1998)
Tetraene 1 was prepared in nine steps from the known propargylic alcohol 7 in 17% overall yield or as a 2:1 E/Z mixture in only five steps in 7% overall yield. Oxidative cyclization of 1 with 2 equiv of Mn(OAc)3·2H2O and 1 equiv of Cu(OAc)2 in MeOH at 25 °C provided 35% of tetracycle 2. Further elaboration provided (±)-isosteviol (3) in six steps in 51% yield and (±)-beyer-15-ene-3β,19-diol in four steps in 17% yield.
Kinetics and Mechanism of Thermal Decomposition of Bis(Η3-Allyl)Nickel Complexes
Flid,Zamalyutin,Shamsiev,Katsman
, p. 113 - 117 (2019/05/27)
Abstract: The kinetics of thermal decomposition of bis(η3-allyl) nickel complexes in various media is studied. The specific features of the mechanism are determined, including the combination of the stages of trans-cis isomerization of Niall2 and the bimolecular decomposition of the cis-isomer with diallyl formation. The effect of autocatalytic decomposition of complexes with metallic nickel is been detected. The qualitative dependences of the process rate on the nature of the solvent and the structure of the allyl ligand are determined. The activation parameters of individual steps, consistent with quantum chemical calculations, are found.
2,2,5,5-Tetramethyltetrahydrofuran (TMTHF): A non-polar, non-peroxide forming ether replacement for hazardous hydrocarbon solvents
Byrne, Fergal,Forier, Bart,Bossaert, Greet,Hoebers, Charly,Farmer, Thomas J.,Clark, James H.,Hunt, Andrew J.
supporting information, p. 3671 - 3678 (2017/08/15)
An inherently non-peroxide forming ether solvent, 2,2,5,5-tetramethyltetrahydrofuran (2,2,5,5-tetramethyloxolane), has been synthesized from readily available and potentially renewable feedstocks, and its solvation properties have been tested. Unlike traditional ethers, its absence of a proton at the alpha-position to the oxygen of the ether eliminates the potential to form hazardous peroxides. Additionally, this unusual structure leads to lower basicity compared with many traditional ethers, due to the concealment of the ethereal oxygen by four bulky methyl groups at the alpha-position. As such, this molecule exhibits similar solvent properties to common hydrocarbon solvents, particularly toluene. Its solvent properties have been proved by testing its performance in Fischer esterification, amidation and Grignard reactions. TMTHF's differences from traditional ethers is further demonstrated by its ability to produce high molecular weight radical-initiated polymers for use as pressure-sensitive adhesives.
Gold(I)-catalyzed intermolecular [2+2] cycloaddition of alkynes with alkenes
Lopez-Carrillo, Veronica,Echavarren, Antonio M.
supporting information; experimental part, p. 9292 - 9294 (2010/11/03)
The gold(I)-catalyzed intermolecular reaction of terminal alkynes with alkenes leads to cyclobutenes. The use of sterically hindered cationic Au(I) complexes as catalysts is key for the success of this reaction.
Factors controlling photochemical cleavage of the energetically unfavorable Ph-Se bond of alkyl phenyl selenides
Ouchi, Akihiko,Liu, Suyou,Li, Zhong,Kumar, S. Ajaya,Suzuki, Toshiaki,Hyugano, Takeshi,Kitahara, Haruo
, p. 8700 - 8706 (2008/03/12)
(Chemical Equation Presented) Primary photochemical paths of alkyl phenyl selenides (1) were investigated, and an origin of large deviations in the chemical yields of products obtained by carbon radical reactions induced by photolysis of phenyl selenides was clarified. KrF excimer laser photolyses of n-pentyl phenyl selenide (1a) yielded 1-pentene (2a), n-pentane (3a), n-decane (4a), dipentyl selenide (5a), benzene (6), dipentyl diselenide (7a), and diphenyl diselenide (7) as major photoproducts, with compounds 2a, 3a, 4a, 5a, and 7 formed by pentyl-Se bond cleavage, and 5a, 6, and 7a by Ph-Se bond cleavage. The selectivity of the photoproducts revealed the occurrence of an unexpected amount of Ph-Se bond cleavage (35% in n-hexane at 248 nm) during photolysis. Solvent viscosity, wavelength of light, and the structure of alkyl substituents were the major factors that controlled Ph-Se bond cleavage. The ratio of Ph-Se bond cleavage decreased with increasing solvent viscosity and laser wavelength. The effect of alkyl substituents on the ratio of bond cleavages, Ph-Se/total C-Se, was investigated for five alkyl phenyl selenides; the ratio decreased in the order pentyl > 2-methylallyl > allyl > 1-ethylpropyl > tert-butyl groups. The contribution of Ph-Se bond cleavage is most probably the origin of the large deviations in the yields of radical reactions induced by photolyses of 1, which can be minimized by selecting appropriate solvents and wavelength of light.
Mechanism of the diphenyldisulfone-catalyzed isomerization of alkenes. Origin of the chemoselectivity: Experimental and quantum chemistry studies
Markovic, Dean,Varela-Alvarez, Adrian,Sordo, Jose Angel,Vogel, Pierre
, p. 7782 - 7795 (2007/10/03)
Polysulfone- and diphenyldisulfone-catalyzed alkene isomerizations are much faster for 2-alkyl-1-alkenes than for linear, terminal alkenes. The mechanism of these reactions has been investigated experimentally for the isomerization of methylidenecyclopentane into 1-methylcyclopentene, and theoretically [CCSD(T)/6-311++G(d,p)//B3LYP/6-311++G(d,p) calculations] for the reactions of propene and 2-methylpropene with a methanesulfonyl radical, MeSO 2?. On heating, polysulfones and (PhSO2)2 equilibrate with sulfonyl radicals, RSO2?. The latter abstract allylic hydrogen atoms in one-step processes giving allylic radical/RSO 2H pairs that recombine within the solvent cage producing the corresponding isomerized alkene and RSO2?. The sulfinic acid, RSO2H, can diffuse out from the solvent cage (H/D exchange with MeOD,D2O) and reduce an allyl radical. Calculations did not support other possible mechanisms such as hydrogen exchange between alkenes, electron transfer, or addition/elimination process. Kinetic deuterium isotopic effects measured for the (PhSO2)2-catalyzed isomerization of methylidenecyclopentane and deuterated analogues and calculated for the H abstraction from 2-methylpropene and deuterated analogues by CH 3-SO2? are consistent also with the one-step hydrogen transfer mechanism. The high chemoselectivity for this reaction is not governed by an exothermicity difference but by a difference in ionization energies of the alkenes. Calculations for CH3SO2? + propene and CH3SO2? + 2-methylpropene show a charge transfer of 0.34 and 0.38 electron, respectively, from the alkenes to the sulfonyl radical in the transition states of these hydrogen abstractions.
Palladium-catalyzed desulfinylative Negishi C-C bond forming cross-couplings of sulfonyl and organozinc chlorides
Dubbaka, Srinivas Reddy,Vogel, Pierre
, p. 3345 - 3348 (2007/10/03)
Arene-, phenylmethane- and alkenesulfonyl chlorides are suitable electrophilic reagents in desulfinylative carbon-carbon bond formation cross-coupling reactions with organozinc reagents.
Enantioselective synthesis of cyclic amides and amines through Mo-catalyzed asymmetric ring-closing metathesis
Sattely, Elizabeth S.,Alexander Cortez,Moebius, David C.,Schrock, Richard R.,Hoveyda, Amir H.
, p. 8526 - 8533 (2007/10/03)
First, an efficient method for the synthesis of optically enriched N-fused bicyclic structures is reported. Through Mo-catalyzed desymmetrization of readily available achiral polyene substrates, 5,6-, 5,7-, and 5,8-bicyclic amides can be synthesized in up to >98% ee. The effects of catalyst structure, olefin substitution, positioning of Lewis basic functional groups and ring size are examined and discussed in detail. In the second phase of investigations, a catalytic asymmetric method for highly enantioselective (up to 97% ee) synthesis of small- and medium-ring unsaturated cyclic amines is reported; optically enriched products bear a secondary amine or a readily removable Cbz or acetamide unit. Regio- and diastereo-selective functionalizations of olefins within the optically enriched amine products have been carried out. Both catalytic asymmetric methods include transformations that lead to the formation of trisubstituted as well as disubstituted cyclic alkenes. The protocols outlined herein afford various cyclic amines of high optical purity; such products are not easily accessed by alternative protocols and can be used in enantioselective total syntheses of biologically active molecules.
Organometallic-type reactions in aqueous media. Wurtz-coupling of alkyl halides with manganese/cupric chloride
Ma, Jihai,Chan, Tak-Hang
, p. 2499 - 2502 (2007/10/03)
Homo-coupling of alkyl halides in aqueous media can be mediated by manganese/cupric chloride to give the dimerisation products in good yield. Cross-coupling can also be controlled to give the desired product.
