90242-33-4Relevant academic research and scientific papers
Ytterbium-Catalyzed Intramolecular [3 + 2] Cycloaddition based on Furan Dearomatization to Construct Fused Triazoles
Xu, Xiaoming,Zhong, Ying,Xing, Qingzhao,Gao, Ziwei,Gou, Jing,Yu, Binxun
supporting information, p. 5176 - 5181 (2020/07/14)
The 1,2,3-triazole-containing polycyclic architecture widely exists in a broad spectrum of synthetic bioactive molecules, and the development of expeditious methods to synthesize these skeletons remains a challenging task. In this work, the catalytic cyclization of biomass-derived 2-furylcarbinols with an azide to form fused triazoles is described. This approach takes advantage of a single catalyst Yb(OTf)3 and operates via a furfuryl-cation-induced intramolecular [3 + 2] cycloaddition/furan ring-opening cascade.
The 2-(2-Azidoethyl)cycloalkanone strategy for bridged amides and medium-sized cyclic amine derivatives in the Aubé-Schmidt reaction
Macleod, Fraser,Lang, Stuart,Murphy, John A.
supporting information; experimental part, p. 529 - 534 (2010/10/02)
2-(2-Azidoethyl)cycloalkanones afford bridged lactams in the Aubé-Schmidt reaction, sometimes in excellent yield, and solvolysis yields derivatives of medium-ring amines. Attempts to divert the Schmidt reaction with an arene-mediated fragmentation of the normal Schmidt intermediate have led to an initial example. Georg Thieme Verlag Stuttgart.
Indirect electroreductive cyclization and electrohydrocyclization using catalytic reduced nickel(II) salen
Miranda, James A.,Wade, Carolyn J.,Little, R. Daniel
, p. 8017 - 8026 (2007/10/03)
We describe efforts to achieve the electroreductive cyclization (ERC) and the electrohydrocyclization (EHC) reactions using catalytic nickel(II) salen as a mediator. While nickel(II) salen proved effective, the analogous cobalt complex as well as nickel(II) cyclam were not. The transformations were achieved in yields ranging from 60 to 94% using either a mercury pool or an environmentally preferable reticulated vitreous carbon (RVC) cathode. These examples represent the first instances wherein a nickel salen complex has been used in this manner. Clear differences between the voltammetric behavior of the ERC and EHC substrates were observed. The bisenoate 14, for example, displays a substantially larger catalytic current. When the structurally modified mediator 31 was used, the electron-transfer pathway shuts down. Instead, the reduced form of 31 behaves as an electrogenerated base, leading to the formation of the intramolecular Michael adduct 23. Presumably, the methyl groups of the modified ligand diminish the ability of the reduced form of the complex to serve as a nucleophile but not as a base. Aldehyde 23 was also characterized as a side product of the nickel(II) salen mediated electroreductive cyclization of 11. Given that it is absent from nonmediated processes, its formation is linked to the presence of the mediator. To account for the results, we favor the existence of a mechanistic continuum involving an equilibrium between nickel(II) salen (15) and two reduced forms, one being the metal-centered species 16, the other being a ligand-centered species 17. We postulate that one form may be more prominently involved with the chemistry than another, depending upon the electronic properties/requirements of the substrate, and suggest that the equilibrium will shift to accommodate the need. Thus, for a hard electrophile like an alkyl halide, the properties of 16 ought to dominate, whereas 17 ought to predominate as the reactive species accounting for the chemistry described herein since it properly matches a soft ligand-centered nucleophile with a soft electron deficient alkene.
Inter- and intramolecular reductive coupling reactions: an approach to the phorbol skeleton.
Carroll,Little
, p. 2873 - 2876 (2007/10/03)
[reaction: see text] An expeditious convergent route to the ABC-tricyclic core of the phorbol esters is described. The chemistry capitalizes upon both inter- and intramolecular reductive coupling processes promoted electrochemically and via the use of sam
Biotransformation of αβ-unsaturated carbonyl compounds: sulfides, sulfoxides, sulfones, nitriles and esters by yeast species: carbonyl group and carbon-carbon double bond reduction
Koul, Surinder,Crout, David H. G.,Errington, William,Tax, Jiri
, p. 2969 - 2988 (2007/10/03)
The reduction of αβ-unsaturated ketones with γ-sulfide, sulfoxide, sulfone, nitrile and ester functions has been investigated.Both C=O and C=C reduction was observed.In the sulfur series, C=O bond reduction was always observed, but significant C=C bond reduction was observed only with the sulfide.The unsaturated nitriles gave the corresponding alcohols as the major bioreduction product, with smaller but significant amounts of fully reduced product.A similar result was obtained with the ester substrate.Relative and absolute configurations of bioreduction products were determined.A comparison was made between reductions catalysed by bakers' yeast (Saccharomyces cerevisiae) and by other yeasts (Zygosaccharomyces rouxii, Pichia capsulata, P. farinosa, Candida chalmersi and C. diddensiae).The tendency of Z. rouxii to give products enantiomeric with thouse obtained using S. cerevisiae was noted.The relationship between substrate structure and the stereochemistry of C=C double bond reduction is discussed.
Preparation of useful intermediates of dextrorphan - Note I
Passarotti,Valenti,Grianti
, p. 472 - 474 (2007/10/02)
Dextrorphan is the main metabolite of Dextromethorphan, a drug with high anti-tussive activity. In this preliminary work we report on the synthesis of two essential intermediates for its preparation: 2-(1-cyclohexenyl)ethyl amine and (R;S)-1-(4-methoxy-benzyl)-2-methyl-1,2,3,4,5,6,7,8-octahydroisoquinol ine.
Electroorganic Chemistry. 140. Electroreductively Intra- and Intermolecular Couplings of Ketones with Nitriles
Shono, Tatsuya,Kise, Naoki,Fujimoto, Taku,Tominaga, Naoto,Morita, Hiroshi
, p. 7175 - 7187 (2007/10/02)
Electroreduction of γ- and δ-cyano ketones in i-PrOH with Sn cathode gave α-hydroxy ketones and their dehydroxylated ketones as the intramolecularly coupled products.Guaiazulene, (-)-valeranone, polyquinanes, dihydrojasmone, methyl dihydrojasmonate, and rosaprostol have been synthesized by utilizing this electroreductive intramolecular coupling of γ- and δ-cyano ketones in one of the key steps.Similarly, electroreduction of a mixture of ketone and nitrile gave the corresponding intermolecularly coupled product.The product obtained by the electroreductive intermolecular coupling of (+)-dihydrocarvone with acetonitrile has been found to be the precursor of an effective chiral ligand for the enantioselective addition of diethylzinc to aldehydes.
SYNTHESE VON γ-HYDROXYNITRILEN, γ-BUTYROLACTONEN UND α-METHYLENO-γ-BUTYROLACTONEN AUS EPOXIDEN UND NATRIUM-
Bestmann, Hans Juergen,Schmidt, Martin
, p. 2111 - 2114 (2007/10/02)
The highly nucleophilic ylide-anion of sodium- attacks oxiranes by ring-opening.Depending on the work-up-conditions and the further reactions being employed, γ-hydroxynitriles, γ-butyrolactones or α-methyleno-γ-butyrolactones are obtained from the primary products thus formed.
Enantiomerically Pure Lactones. 2. Approaches to Cis or Trans Multicyclic Lactones
Pirkle, William H.,Adams, Paul E.
, p. 4111 - 4117 (2007/10/02)
Enantiomerically pure bicyclic lactones 1-3 and tricyclic lactones 4 and 5 have been prepared by either of two procedures, each hinging upon the liquid chromatographic seperation of rationally selected diastereomeric derivatives.After seperation, the diastereomers are converted by a simple high-yield reaction sequence to the enantiomeric multiring lactones, none of which has been previously reported in optically active form. The relative strengths and weaknesses of each approach are discussed.Lactones 4 and 5 were α-methylated, these derivatives being suitable for the determination of enantiomeric purity and absolute configuration using the chiral solvating agent (S)-(+)-2,2,2-trifluoro-1-(9-anthryl)ethanol.
