Results 151 to 160 of about 754 (188)
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ChemInform Abstract: α‐SUBSTITUTION‐SPIROANNULATION OF SATURATED KETONES
Chemischer Informationsdienst, 1984AbstractDas mit Cyclopentanon als Ausgangsketon dargestellte Trimethylsilyloxy‐cyclopropan (I) lagert sich in Gegenwart des Brom‐Dioxan‐Komplexes in das Bromspiroketon (II) um, das bei der Oxidation mit MCPBA das Bromlacton (III) gibt.
B. M. TROST, M. K.‐T. MAO
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The Journal of Organic Chemistry, 2023
A novel [4 + 1] and [5 + 1] dearomative spiroannulation has been developed by the use of commercial naphthols and phenols with dielectrophiles. Various spirocycles, including spiro[4.5] and spiro[5.5] have been constructed successfully by employing four-atom or five-atom dielectrophilic synthons.
Dongwei Zhao +4 more
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A novel [4 + 1] and [5 + 1] dearomative spiroannulation has been developed by the use of commercial naphthols and phenols with dielectrophiles. Various spirocycles, including spiro[4.5] and spiro[5.5] have been constructed successfully by employing four-atom or five-atom dielectrophilic synthons.
Dongwei Zhao +4 more
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Organic Letters, 2023
A dearomatization/spiroannulation process has been successfully achieved between simple halophenols and α,β-unsaturated olefins under mild reaction conditions. This transformation addresses the chemoselectivity issue in the dearomatizative transformation of phenol scaffolds (6π-electron) caused by the SEAr process, enabling the construction of ...
Sichan Dong +5 more
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A dearomatization/spiroannulation process has been successfully achieved between simple halophenols and α,β-unsaturated olefins under mild reaction conditions. This transformation addresses the chemoselectivity issue in the dearomatizative transformation of phenol scaffolds (6π-electron) caused by the SEAr process, enabling the construction of ...
Sichan Dong +5 more
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ChemInform Abstract: ORGANOBISCUPRATES. A SINGLE‐STEP SPIROANNULATION METHOD
Chemischer Informationsdienst, 1977AbstractAus den Lw‐Dilithiopolymethylenen (I) erhält man mit Cu(I)‐thiophenolat (II) die Komplexe (III), die mit Benzoylchlorid zu den Diketonen (Va) und (Vb) führen.
P. A. WENDER, S. L. ECK
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Target cum flexibility: synthesis of C(3′)-spiroannulated nucleosides
Tetrahedron Letters, 2011We report a simple strategy for the synthesis of a collection of C(3′)-spirodihydroisobenzo-furannulated nucleosides featuring a [2+2+2]-cyclotrimerization as the key reaction. The cyclotrimerization reactions are facile with the unprotected nucleosides having a diyne unit.
Mangesh P. Dushing, C.V. Ramana
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Cycloisomerisations in Pd‐Catalysed Spiroannulations onto Chiral Pyrazine Derivatives
European Journal of Organic Chemistry, 2002AbstractA method for 5‐exo‐trig‐spiroannulations is described which uses the Pd complex trans‐bis(μ‐acetato)bis[o‐(di‐o‐tolylphosphanyl)benzyl]dipalladium(II) as catalyst in cyclisation reactions of dienes with the chiral auxiliary (2R)‐2,5‐dihydro‐2‐isopropyl‐3,6‐dimethoxypyrazine.
Bjørg Møller, Kjell Undheim
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ChemInform Abstract: CYCLOCONTRACTION ‐ SPIROANNULATION: A STEREOSELECTIVE APPROACH TO SPIROCYCLES
Chemischer Informationsdienst, 1983AbstractDie Umsetzung der Ketosulfone (I) mit der Al‐Spezies (II) führt durch Cyclisierung [‐ (III)] und Ringkontraktion/Isomerisierung zu den Spirocyclen (V).
B. M. TROST, B. R. ADAMS
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Dearomative [2 + 1] Spiroannulation of Bromophenols with Electron-Deficient Alkenes
The Journal of Organic ChemistryA base-assisted dearomative [2 + 1] spiroannulation of p/o-bromophenols with activated olefins (methylenemalonates) to construct various cyclopropyl spirocyclohexadienone skeletons is reported. Furthermore, several other halophenols (X = Cl, I) were also tolerated in this process.
Ting-Ting Yang +5 more
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Studies Directed to the Synthesis of New C‐5 Spiroannulated Julolidines.
ChemInform, 2002AbstractFor Abstract see ChemInform Abstract in Full Text.
Alirio Palma +6 more
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Rh(III)-Catalyzed Diastereodivergent Spiroannulation of Cyclic Imines with Activated Alkenes
Organic Letters, 2017Rh(III)-catalyzed [3 + 2] annulation of cyclic N-sulfonyl or N-acyl ketimines with activated alkenes has been realized, leading to the synthesis of spirocycles with three continuous stereogenic centers. This atom-economic reaction proceeded efficiently under mild and redox-neutral conditions via a C-H activation pathway, and the coupling is ...
Bingxian Liu +5 more
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