نتایج جستجو برای: phosphorus ylide
تعداد نتایج: 41924 فیلتر نتایج به سال:
Aryl chalcones rearrange and add methanol to give substituted propane-1-ones upon UV-A irradiation in the presence of PPh3. We propose two possible mechanisms for this photo-rearrangement. The reaction involves either the formation of a phosphine-carbonyl intermediate, nucleophilic addition of MeOH and 1,2-aryl migration or the formation of ylide and carbene intermediates. The intermediates tra...
We have devised a highly regio- and enantioselective iridium-catalyzed allylic amination reaction with the sulfur-stabilized aza-ylide, S,S-diphenylsulfilimine. This process provides a robust and scalable method for the construction of aryl-, alkyl- and alkenyl-substituted C-chiral allylic sulfilimines, which are important functional groups for organic synthesis. Additionally, the combination o...
Lewis base catalysed 1,3-dipolar cycloaddition between α,β-unsaturated acyl fluorides and N-[(trimethylsilyl)methyl]amino ethers has been achieved using 1 mol% DMAP. Competition experiments and (19)F-NMR studies indicate that the cycloaddition occurs preferentially between the α,β-unsaturated acyl fluoride and the unstabilised azomethine ylide. In addition, an enantioselective variant, using ch...
The title compound, C(21)H(21)N(3)O(3), was synthesized by a multi-component 1,3-dipolar cyclo-addition of azomethine ylide, derived from isatin and proline by a deca-rboxylative route, and (E)-1-phenyl-2-nitro-propene. In the mol-ecule, the spiro junction links a planar oxindole ring and a pyrrolidine ring in an envelope conformation. The mol-ecular packing is stabilized by an inter-molecular ...
A series of hitherto unreported anthracene-embedded dispirooxindoles has been synthesized via a one-pot three-component 1,3-dipolar cycloaddition reaction of an azomethine ylide, generated in situ from the reaction of isatin and sarcosine to 10-benzylideneanthracen-9(10H)-one as a dipolarophile in 1-butyl-3-methylimidazolium bromide([bmim]Br), an ionic liquid. This reaction proceeded regio- and...
An efficient synthetic approach to the core structure of the manzamine alkaloids is reported, particularly in relation to incorporating a one-carbon unit in ring B from which the aldehyde in ircinal A or the beta-carboline unit in manzamine A could potentially be generated. The key steps involve a Johnson-Claisen rearrangement, enolate alkylation, dithiane alkylation and a stereoselective intra...
The preparation of potassium hydride as a 1:1 homogenate with paraffin, termed KH(P), is reported. KH(P), a solid at room temperature, is stable without special handling. On suspension in THF with a phosphonium salt, KH(P) rapidly generates the ylide. Wittig condensation with aromatic, aliphatic, and alpha,beta-unsaturated aldehydes proceeds with high Z selectivity. KH(P) should be a generally ...
We have presented a near-infrared fluorescent probe Lyso-JN for the detection of nitroxyl (HNO) in cells and in vivo. Lyso-JN is comprised of three moieties: an Aza-BODIPY fluorophore, a HNO-response modulator, diphenylphosphino-benzoyl, and a lysosomal locator, alkylmorpholine. The detection mechanism is based on aza-ylide intramolecular ester aminolysis reaction with HNO. The probe holds the ...
A novel nitrogen-doped corannulene derivative, 8-tert-butyl-6b(2) -azapentabenzo[bc,ef,hi,kl,no]corannulene, was synthesized by 1,3-dipolar cycloaddition of a polycyclic aromatic azomethine ylide with a diarylethyne and subsequent palladium-catalyzed intramolecular cyclization. This molecule represents the first example of a corannulene derivative bearing an internal heteroatom, and exhibits un...
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