نتایج جستجو برای: 13 dipolar cycloaddition
تعداد نتایج: 343672 فیلتر نتایج به سال:
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 [2+3] dipolar cycloaddition of nitrile oxides to the double C = C bonds of thiophene-1, 1-dioxides leads to formation of the fused isoxazolines-2 (1, 2). Tumor growth inhibition of these compounds strongly depends on the nature of group IV A element increasing from slightly active tert-butyl derivatives to silicon and germanium containing analogues. The products of benzonitrile oxide cycloa...
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This work reports for the first time a straightforward solvent-free chemical procedure to gain access to Δ-1-pyrroline grafted onto multiwalled carbon nanotubes by the 1,3-dipolar cycloaddition of the mesoionic 4-methyl-2-phenyloxazol-5(4H)-one.
The diversely functionalized tricyclic tetrazoles were synthesised from readily available substrates via intramolecular 1,3-dipolar cycloaddition as the key step in good yields (53-78% yield for two steps) with high enantioselectivities (81-99% ee).
Five-fold symmetric substituted corannulene derivatives that display liquid-crystalline behavior and organogelation properties were prepared by coupling of N-azidoethyl long-chain fatty acid amides to sym-pentabutynyl corannulenes via dipolar cycloaddition chemistry.
Condensation of an aldehyde with an α-amino-ester, followed by a tandem process involving cyclization to a seven-membered ring, deprotonation to an intermediate azomethine ylide and intramolecular dipolar cycloaddition gave tricyclic products related to stenine and neostenine.
[reaction: see text] A novel Cu(I)-catalyzed asymmetric 1,3-dipolar cycloaddition of azomethine ylides with acrylates has been developed. Up to 98/2 exo/endo selectivity and up to 98% enantiomeric excess have been achieved.
A strategy for exo and enantioselective 1,3-dipolar cycloaddition of azomethine imines to 2-acryloyl-3-pyrazolidinone is described. The corresponding cycloadducts are isolated with high diastereoselectivities (up to >96:4 exo/endo) and enantioselectivities (up to 98% ee).
A Cu(I)-catalyzed 1,3-dipolar cycloaddition was used to construct a monolayer of an altitudinal molecular motor on quartz and silicon substrates, which represents the fastest light-driven molecular motor, to date, grafted to a solid surface.
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