Results 131 to 140 of about 490 (165)

Target cum flexibility: synthesis of C(3′)-spiroannulated nucleosides

Tetrahedron Letters, 2011
We 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
openaire   +1 more source

Silver-Catalyzed Dearomative [3+2] Spiroannulation of Aryl Oxamic Acids with Alkynes

Synthesis
A silver-catalyzed dearomative decarboxylative [3+2] spiroannulation of aryl oxamic acids with alkynes is described. The reaction provides reliable access to a range of azaspiro[4,5]trienones in moderate yields in aqueous media. In addition, the reaction
Cheng-An Jin, Ren-Xiao Liang, Yi‐Xia Jia   +2 more
semanticscholar   +1 more source

Au(I)/Sc(III)-co-catalyzed tandem spiroannulation/cycloisomerization of 3-(2-ethynylaryl)-N-tosylaziridines with indoles to access 5H-benzo[b]carbazoles.

Organic and biomolecular chemistry
An unusual spiroannulation/cycloisomerization cascade of 3-(2-ethynylaryl)-N-tosylaziridines with indoles enabled by cooperative gold/scandium catalysis is presented, which facilitates the synthesis of 5H-benzo[b]carbazoles in moderate to excellent ...
Wei Wang, Lan Zheng, Wen-Jie Liang, Xin Fu, Yu-Qing Zhang, Ru-Fang Meng, Huan Zhang, Chenxiang Lin, Wei-Chun Su, Jun‐An Xiao   +9 more
semanticscholar   +1 more source

Cycloisomerisations in Pd‐Catalysed Spiroannulations onto Chiral Pyrazine Derivatives

European Journal of Organic Chemistry, 2002
AbstractA 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
openaire   +1 more source

Efficient Synthesis of Benzospirocyclohexadienones via PIFA-Promoted Intramolecular Dearomative Spiroannulation

Synthesis
A rapid and convenient method for the synthesis of differently substituted spiro[cyclohexane-1,1′-isochromane]-2,5-dien-4-one derivatives via phenyliodine(III) bis(trifluoroacetate) (PIFA)-promoted intramolecular oxidative dearomatization at the para ...
Xinkun An, Tingting Zhang, Haoyun Ma, Xie He, Mingan Wang   +4 more
semanticscholar   +1 more source

Convergent Assembly of 1,4-Benzothiazide Spiroindolinones via [4 + 2] Spiroannulation Under Open-Air Conditions.

Journal of Organic Chemistry
This report discloses a transition-metal-free [4 + 2] spirocyclization of isatin-derived β-silylcarbinols and 2-aminobenzenethiols, providing a facile approach to 1,4-benzothiazide spiroindolinones in decent yields.
Wenjie Hu, Kai-Heng Yu, Fengcheng Jia, Shuangxi Gu   +3 more
semanticscholar   +1 more source

Synthesis of Pyrazolo[1,2‐a]indazoles via Iridium(III)‐Catalyzed [4+1] Spiroannulation Reaction of Pyrazolidinones and 2‐Diazo‐1,3‐indandiones

Asian Journal of Organic Chemistry
A novel protocol for synthesizing pyrazolo[1,2‑a]indazoles from readily available pyrazolidinones and 2‐diazo‐1,3‐indandiones through the Ir(III)‐catalyzed C─H bond activation and intramolecular spiroannulation reaction has been described.
Zi-Mo Yang, Qiuzi Dai, Jianjun Lin, Jieni Lei, Yaqian Li, Chao Liu, Xin Li   +6 more
semanticscholar   +1 more source

Ru(II)‐Catalyzed Spiroannulation of 2‐Arylindole‐3‐carbaldehydes and 2‐Arylquinazolinones With 1,4‐Quinones

ChemistrySelect
A simple, convenient and efficient method for the spiroannulation of 2‐arylindole‐3‐carbaldehydes and 2‐arylquinazolinones with 1,4‐quinones has been reported.
Rajini Raja, Ramesh Sanjana, K. Parthasarathy   +2 more
semanticscholar   +1 more source

Synthesis of Spironitrodihydroacridines via Formal [5 + 1] Spiroannulation and Nitroso Group Oxidative Migration.

Organic Letters
Presented herein is a cascade reaction featuring multiple-C-H bond activation-initiated formal [5 + 1] spiroannulation along with simultaneous nitroso group oxidative migration of N-nitrosodiarylamine with a diazo compound.
Yuqian Sun, Jiayi Zou, Yijun Gong, Chunhua Ma, Xinying Zhang, Xuesen Fan   +5 more
semanticscholar   +1 more source

peri-Selective C-H activation-initiated spiroannulation leading to spiropolycyclic compounds with unique photophysical properties and strong anticancer activity.

Chemical Communications
Presented herein is a peri-selective C-H activation-initiated spiroannulation leading to an effective and concise construction of spirocyclic skeletons.
Qianting Zhou, Jiayi Zou, Haiyun Xu, Yijun Gong, Chunhua Ma, Xinying Zhang, Xuesen Fan   +6 more
semanticscholar   +1 more source