Results 131 to 140 of about 337 (160)
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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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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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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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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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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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Journal of the Chemical Society, Chemical Communications, 1990
A new approach to the title ring system, required for the development of potential aromatase inhibitors, is described; acid chlorides (6) and (12) undergo an unusual addition–cyclisation reaction with alkynes, catalysed by aluminium chloride, to yield tricyclospirodienones (7) and (13).
F. Thomas Boyle +3 more
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A new approach to the title ring system, required for the development of potential aromatase inhibitors, is described; acid chlorides (6) and (12) undergo an unusual addition–cyclisation reaction with alkynes, catalysed by aluminium chloride, to yield tricyclospirodienones (7) and (13).
F. Thomas Boyle +3 more
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Organic Letters
Herein, we report a cascade reaction to produce spirophthalide boronate frameworks efficiently. This protocol involves borylcupration as a cascade triggering reaction followed by intramolecular aldol reaction, hemiacetalization, and subsequent oxidation, allowing the formation of optically pure spirophthalide boronates with excellent enantio- and ...
Laxman Devidas Khalse +2 more
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Herein, we report a cascade reaction to produce spirophthalide boronate frameworks efficiently. This protocol involves borylcupration as a cascade triggering reaction followed by intramolecular aldol reaction, hemiacetalization, and subsequent oxidation, allowing the formation of optically pure spirophthalide boronates with excellent enantio- and ...
Laxman Devidas Khalse +2 more
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Dearomative spiroannulation of indoles enabled by the diaza-[1,2]-Wittig rearrangement
Organic Chemistry FrontiersReported herein is the first diaza-[1,2]-Wittig rearrangement-enabled dearomative spiroannulation reaction of indoles. This protocol features metal-free conditions, a redox-neutral process, a broad substrate scope, and a good yield.
Can Luo +4 more
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