145126-90-5Relevant academic research and scientific papers
Ring-closing metathesis of vinyl fluorides towards α-fluorinated α,β-unsaturated lactams and lactones
Marhold, Michael,Stillig, Christian,Fr?hlich, Roland,Haufe, Günter
supporting information, p. 5777 - 5785 (2014/10/15)
Ring-closing olefin metathesis reactions (RCM) using Grubbs II or Hoveyda's catalysts have been applied to a series of N-alkenyl-N-benzyl-α-fluoroacrylamides. α-Fluoro-α,β-unsaturated γ- or δ-lactams incorporating a fluorinated double bond were obtained in moderate to good yields, depending on the nature of substituents on the benzyl ring. The corresponding seven- and eight-membered lactams were not formed under similar conditions. When the N-benzyl group was replaced by an N-tosyl group, the corresponding ε-lactam was also formed in 38% yield. When N-(2-fluoroallyl) derivatives were used instead of fluoroacryloyl derivatives, six-, seven-, and eight-membered N-heterocycles were obtained in low yields. This method was also used to synthesize fluorinated α,β-unsaturated analogues of pyrrolizidine and indolizidine alkaloids from prolinol, and also to synthesize N-benzyl-3-fluoroquinolone in three steps from commercially available 2-vinylaniline in 44% overall yield. Also 3-fluorocoumarin and 3-fluorochromene were prepared from ovinylphenol, and 3-fluoro-benzoxepine was available from o-allylphenol.
Molecular complexity via C-H activation: A dehydrogenative Diels-Alder reaction
Stang, Erik M.,White, M. Christina
supporting information; experimental part, p. 14892 - 14895 (2011/11/01)
Traditionally, C-H oxidation reactions install oxidized functionality onto a preformed molecular skeleton, resulting in a local molecular change. The use of C-H activation chemistry to construct complex molecular scaffolds is a new area with tremendous potential in synthesis. We report a Pd(II)/bis-sulfoxide- catalyzed dehydrogenative Diels-Alder reaction that converts simple terminal olefins into complex cycloadducts in a single operation.
Mild nonepimerizing N -alkylation of amines by alcohols without transition metals
Guerin, Claire,Bellosta, Veronique,Guillamot, Gerard,Cossy, Janine
supporting information; experimental part, p. 3534 - 3537 (2011/08/10)
A one-pot two-step sequence involving an oxidation/imine-iminium formation/reduction allowed the N-alkylation of amines by alcohols without any epimerization when optically active alcohols and amines are involved in the process.
Mild, rhodium-catalyzed intramolecular hydroamination of unactivated terminal and internal alkenes with primary and secondary amines
Liu, Zhijian,Hartwig, John F.
, p. 1570 - 1571 (2008/09/17)
We report a series of mild, rhodium-catalyzed hydroaminations of unactivated olefins with primary and secondary alkylamines to form the corresponding five- and six-membered products in excellent yields. The reactions form exclusively the product from hydroamination without competitive oxidative amination or olefin isomerization with catalysts generated from a biaryl dialkyl phosphine and an analogue of Xantphos. A variety of functional groups were tolerated by the hydroamination process, including hydroxyl, halo, cyano, and carboalkoxyl groups. Copyright
Low background FRET-substrates for lipases and esterases suitable for high-throughput screening under basic (pH 11) conditions
Yang, Yongzheng,Babiak, Peter,Reymond, Jean-Louis
, p. 1746 - 1754 (2008/03/11)
FRET-based fluorogenic substrates for lipases and esterases were prepared in four steps from commercially available building blocks. The substrates are pyrenebutyric acid monoesters of aliphatic 1,2-diols bearing a dinitrophenylamino group as a quencher. The most enzyme-reactive substrate is ester 2a. The substrates do not show any measurable background reaction in the absence of enzyme even at pH 11, but react fast and specifically with lipases and esterases. These substrates offer an unprecedented and practical solution to the long-standing problem of a simple yet efficient high-throughput screening tool for lipase activities under basic conditions. The Royal Society of Chemistry 2006.
Synthesis of medium and large cyclic amines in rhodium-catalysed reactions of aminoalkenes with H2/CO1
Bergmann, David J.,Campi, Eva M.,Roy Jackson,Patti, Antonio F.,Saylik, Dilek
, p. 835 - 844 (2007/10/03)
Rhodium-catalysed reactions of N-benzyl- or N-alkyl-aminoalkenes (6) with H2/CO can give cyclic amines (7) (7-13 ring size) in good to excellent yields when BIPHEPHOS is used as a ligand. Hydrogenation of the aminoalkene becomes a competing reaction for the smaller rings but can be overcome by using a H2/CO gas ratio of 1:5. Reactions of 2-alkenyloxybenzylamines (13) gave 9-, 12- and 17-membered rings (14) in 30-40% yield, but dimer formation (16) and/or hydrogenation were competing reactions. Similar reactions of alkenylamides and ortho-alkenylanilines gave only non-cyclized amino aldehydes as products in low isolated yields.
Radical Cyclisation in Heterocycle Synthesis. Part 1. Sulfanyl Radical Addition-Cyclisation of Dienylamides for Lactam Synthesis
Naito, Takeaki,Honda, Yuko,Miyata, Okiko,Ninomiya, Ichiya
, p. 19 - 26 (2007/10/02)
A new method for the synthesis of five- to eight-membered lactams by sulfanyl radical mediated-cyclisation of dienylamides is described.The sulfanyl radical addition-cyclisation of the dienylamide 1 was systematically investigated under four different conditions and was found to give the cyclised lactams 2-6 in 54-79percent yield.The stereo- and regio-selectivity of sulfanyl radical addition-cyclisation was established from the preferential formation of the trans-cyclised lactam 3 and also from the substituent effects in the cyclisation of the dienylamides 11-18.The sulfanyl radical mediated addition-cyclisation was successfully applied to the construction of the six- and eight-membered lactams 28a, b.
Radical Translocation Reactions across Amides. 1,5-Hydrogen-Transfer Reactions of o-Iodobenzamides and N-(o-Iodobenzyl) Amides
Curran, Dennis P.,Liu, Hohgtao
, p. 1377 - 1394 (2007/10/02)
Radicals derived from N,N-disubstituted o-iodobenzamides undergo rapid 1,5-hydrogen-transfer reactions.The regioselectivity of these reactions is coupled to the rotamer population of the starting iodobenzamide, and the products vary with changing amide substituents.Related 1,5-hydrogen-transfer reactions are observed for N-alkyl-N-(o-iodobenzyl)-benzamides and -acetamides.
Intramolecular 1,3-Dipolar Cycloaddition of Stabilized Azomethine Ylides to Unactivated Dipolarophiles
Henke, Brad R.,Kouklis, Andrew J.,Heathcock, Clayton H.
, p. 7056 - 7066 (2007/10/02)
The scope and limitations of the intramolecular 1,3-dipolar cycloaddition of doubly-stabilized azomethine ylides to unactivated olefinic, acetylenic, and aromatic dipolarophiles is reported.The azomethine ylides studied were generated by flash vacuum pyrolysis of their corresponding aziridines and were found to add stereospecifically in good to excellent yields to a variety of unactivated dipolarophiles.Generation of the diazabicyclooctane (e.g., 15a,b), diazabicyclononane (e.g., 4, 13), and diazabicyclodecane (e.g., 15c) ring systems are possible using this technology.In addition, the first examples of cycloaddition of a stabilized azomethine ylide to benzene dipolarophiles are reported.Cycloadditions of this type generate highly functionalized tricyclic systems with complete relative stereocontrol at the newly formed stereocenters (e.g., 24-26).Finally, it has been shown that cycloadducts 31 and 32 are in equilibrium, presumably by way of the intermediate azomethine ylide 33, under conditions of flash vacuum pyrolysis.
