4393-21-9Relevant academic research and scientific papers
Rh(iii)-Catalyzed allylic C-H amidation of unactivated alkenes within situgenerated iminoiodinanes
Jeganmohan, Masilamani,Sihag, Pinki
, p. 6428 - 6431 (2021/07/02)
Rh(iii)-catalyzed allylic C-H amidation of substituted alkenes within situgenerated iminoiodinanes is demonstrated. The presented protocol is compatible with differently functionalized unactivated terminal alkenes and internal alkenes. In terminal alkenes
Evidence for a Sigmatropic and an Ionic Pathway in the Winstein Rearrangement
Ott, Amy A.,Packard, Mary H.,Ortuno, Manuel A.,Johnson, Alayna,Suding, Victoria P.,Cramer, Christopher J.,Topczewski, Joseph J.
, p. 8214 - 8224 (2018/06/13)
The spontaneous rearrangement of allylic azides is thought to be a sigmatropic reaction. Presented herein is a detailed investigation into the rearrangement of several allylic azides. A combination of experiments including equilibrium studies, kinetic ana
A short synthesis of pyridines from deprotonated α-aminonitriles by an alkylation/RCM sequence
Weber, Carina,Nebe, Marco M.,Kaluza, Lukas P. V.,Opatz, Till
, p. 633 - 641 (2016/07/06)
α-Aminonitriles can serve as versatile key precursors for the synthesis of nitrogen containing heterocycles. After unsuccessful trials involving the [1,2]-Stevens rearrangement of nitrile-stabilized ammonium ylides, we herein report a simple three-step synthesis of substituted pyridines based on an alkylation/ring-closing metathesis/aromatization sequence.
Rhodium-Catalyzed Regiodivergent Hydrothiolation of Allyl Amines and Imines
Kennemur, Jennifer L.,Kortman, Gregory D.,Hull, Kami L.
supporting information, p. 11914 - 11919 (2016/10/06)
The regiodivergent Rh-catalyzed hydrothiolation of allyl amines and imines is presented. Bidentate phosphine ligands with larger natural bite angles (βn ≥ 99°), for example, DPEphos, dpph, or L1, promote a Markovnikov-selective hydrothiolation in up to 88% yield and >20:1 regioselectivity. Conversely, when smaller bite angle ligands (βn ≤ 86°), for example, dppbz or dppp, are employed, the anti-Markovnikov product is formed in up to 74% yield and >20:1 regioselectivity. Initial mechanistic investigations are performed and are consistent with an oxidative addition/olefin insertion/reductive elimination mechanism for each regioisomeric pathway. We hypothesize that the change in regioselectivity is an effect of diverging coordination spheres to favor either Rh-S or Rh-H insertion to form the branched or linear isomer, respectively.
Flexible synthesis of polyfunctionalised 3-fluoropyrroles
Cogswell, Thomas J.,Donald, Craig S.,Marquez, Rodolfo
supporting information, p. 183 - 190 (2015/12/30)
An efficient and selective approach for the synthesis of polyfunctionalised 3-fluoropyrroles has been developed starting from commercial aldehydes. The methodology is concise, efficient and allows for the modular and systematic assembly of polysubstituted 3-fluoropyrroles. This synthesis provides an alternative and highly convergent strategy for the generation of these chemically and biologically important units.
Palladium-catalyzed anti-markovnikov oxidation of allylic amides to protected β-amino aldehydes
Dong, Jia Jia,Harvey, Emma C.,Faans-Mastral, Martn,Browne, Wesley R.,Feringa, Ben L.
supporting information, p. 17302 - 17307 (2015/02/05)
A general method for the preparation of N-protected β-amino aldehydes from allylic amines or linear allylic alcohols is described. Here the Pd(II)-catalyzed oxidation of N-protected allylic amines with benzoquinone is achieved in tBuOH under ambient conditions with excellent selectivity toward the anti-Markovnikov aldehyde products and full retention of configuration at the allylic carbon. The method shows a wide substrate scope and is tolerant of a range of protecting groups. Furthermore, β-amino aldehydes can be obtained directly from protected allylic alcohols via palladium-catalyzed autotandem reactions, and the application of this method to the synthesis of β-peptide aldehydes is described. From a mechanistic perspective, we demonstrate that tBuOH acts as a nucleophile in the reaction and that the initially formed tert-butyl ether undergoes spontaneous loss of isobutene to yield the aldehyde product. Furthermore, tBuOH can be used stoichiometrically, thereby broadening the solvent scope of the reaction. Primary and secondary alcohols do not undergo elimination, allowing the isolation of acetals, which subsequently can be hydrolyzed to their corresponding aldehyde products.
An efficient enzymatic approach to (S)-1-aryl-allylamines
Knezevic, Anamarija,Landek, Goran,Dokli, Irena,Vinkovic, Vladimir
experimental part, p. 936 - 941 (2011/09/20)
A range of 1-aryl-allylamines were prepared in moderate to excellent enantioselectivity (ee 63.5%→99.9%) using lipase B from a Candida antarctica catalyzed resolution of racemic amines. This is the first time that CaLB has been used for the resolution of 1-aryl-allylamines. Racemic amines were prepared starting from aromatic aldehydes with a [3,3]-sigmatropic rearrangement of the acyclic imidates as the key step followed by trichloroacetamidate hydrolysis. Aldehydes were converted into acrylic esters using Knoevenagel reaction. After reduction, the corresponding alcohols were used for the preparation of trichloroacetimidates, which were then used in an Overman rearrangement.
NEW CHIRAL STATIONARY PHASES FOR CHROMATOGRAPHY BASED ON AROMATIC ALLYL AMINES
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Page/Page column 7-8; Figure 1, (2009/10/22)
New chiral stationary phases (CSPs) based on chiral selectors covalently bound on a solid support were prepared. Chiral selectors were obtained from enantiomerically pure aromatic amines and 3,5-dinitrobenzoic acid and then linked to the support surface through the allylic double bond. Such obtained materials allow enantioseparation of racemates or enantiomerically enriched compounds. These chiral stationary phases can be used as fillings in chromatographic columns for enantiomer separation of naproxen type drugs and other similar non-steroidal anti-inflammatory drugs (NSAID) by means of high performance liquid chromatography on both the analytical and preparative scale.
Asymmetric synthesis of N-protected amino acids by the addition of organolithium carboxyl synthons to ROPHy/SOPHy-derived aldoximes and ketoximes.
Cooper, Tracey S,Laurent, Pierre,Moody, Christopher J,Takle, Andrew K
, p. 265 - 276 (2007/10/03)
A new asymmetric synthesis of alpha-amino acids is described in which the key step is the highly diastereoselective addition of organolithium carboxyl synthons (2-furyllithium, phenyllithium, vinyllithium) to (R)- and (S)-O-(1-phenylbutyl) oximes to give hydroxylamines, with vinyllithium being the most satisfactory nucleophilic reagent. Subsequent reductive cleavage of the N-O bond in hydroxylamines, followed by N-protection, and oxidative cleavage of the carboxyl precursor gave a range of N-protected amino acids and esters. The method was exemplified by the synthesis of a range of derivatives of non-proteinogenic amino acids such as 4-bromophenylalanine, tert-leucine, norvaline, cyclohexyl- and aryl-glycines, 2-amino-8-oxodecanoic acid (Aoda) and alpha-methylvaline.
Enantioselective synthesis of 1-aryl-2-propenylamines: A new approach to a stereoselective synthesis of the Taxol side chain
Castagnolo, Daniele,Armaroli, Silvia,Corelli, Federico,Botta, Maurizio
, p. 941 - 949 (2007/10/03)
A variety of substituted 1-aryl-2-propenylamines of high enantiomeric purity were prepared via lipase-catalysed resolution of the corresponding racemates. (R)-1-Phenyl-2-propenylamine was further synthesised into (2R,3S)-3-benzoylamino-2-hydroxy-3-phenylpropanoic acid methyl ester, the side chain of Taxol.
