- Copper-Catalyzed Oxy-Alkynylation of Diazo Compounds with Hypervalent Iodine Reagents
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Alkynes have found widespread applications in synthetic chemistry, biology, and materials sciences. In recent years, methods based on electrophilic alkynylation with hypervalent iodine reagents have made acetylene synthesis more flexible and efficient, but they lead to the formation of one equivalent of an iodoarene as side-product. Herein, a more efficient strategy involving a copper-catalyzed oxy-alkynylation of diazo compounds with ethynylbenziodoxol(on)e (EBX) reagents is described, which proceeds with generation of nitrogen gas as the only waste. This reaction is remarkable for its broad scope in both EBX reagents and diazo compounds. In addition, vinyl diazo compounds gave enynes selectively as single geometric isomers. The functional groups introduced during the transformation served as easy handles to access useful building blocks for synthetic and medicinal chemistry.
- Hari, Durga Prasad,Waser, Jerome
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p. 2190 - 2193
(2016/03/08)
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- Study on the selectivity in the electrophilic monofluorination of 2,3-allenoates with Selectfluor: An efficient synthesis of 4-fluoro-2(5H)-furanones and 3-fluoro-4-oxo-2(E)-alkenoates
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Different from the reaction of 2,3-allenoic acids with Selectfluor, 4-fluoro-2(5H)-furanones and (E)-3-fluoro-4-oxo-2-alkenoates were highly selectively generated from 2,4-disubstituted 2,3-allenoates with Selectfluor under different conditions in moderate yields. The reaction of 2, 4, 4-trisubstituted 2,3-allenoates afforded the corresponding 4-fluoro-2(5H)-furanones highly selectively with up to 95% yield under different conditions. The scope of the substrates has been carefully explored. Due to the more readily availability of 2,3-allenoates as compared to 2,3-allenoic acids, new 4-fluoro-2(5H)furanones were prepared. Based on the isolation and characterization of the minor fluorohydroxylation product E-5m, a mechanism has been proposed. The Royal Society of Chemistry 2010.
- Lue, Bo,Fu, Chunling,Ma, Shengming
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supporting information; experimental part
p. 274 - 281
(2010/04/24)
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- Ruthenium-catalyzed two-component addition to form 1,3-dienes: Optimization, scope, applications, and mechanism
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A two component coupling of an allene and an activated olefin to form 1,3-dienes has been developed. The requisite allenes are synthesized either from terminal alkynes by a one carbon homologation using copper(I) iodide, paraformaldehyde, and diisopropyla
- Trost,Pinkerton,Seidel
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p. 12466 - 12476
(2007/10/03)
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- Synthesis and Structure of Carbonyliron Complexes of Allenecarboxylates and Allenic Lactones
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On irradiation in the presence of Fe(CO)5, the allenecarboxylates 1 afforded binuclear carbonyliron complexes 6 (Scheme 3), whereas the allenic lactone 7 under similar conditions gave a mixture of one binuclear and two mononuclear carbonyliron complexes (9, 8, and 10; Scheme 4).The structure of the complexes has been elucidated by X-ray crystallography.The structure of the binuclear complex 9 corresponds to that of 6, while 8 has been shown to be a 1,3-butadiene(tricarbonyl)iron complex.The unique structure of 10 represents a new type of allenic complex.A stepwise formation of the complexes via intermediate allene(tetracarbonyl)iron complexes of type 11 and 13 is suggested.Treatment of the binuclear complex 6b with FeCl3 led to the formation of the free ligand and a mixture of mononuclear complexes 13 and 14 (Scheme 5).On heating, the 1,3-diene complex 8 yielded the free ligand 15, the product of a (1,3) H shift in the allene 7; the complex 10 on the other hand liberates 7 on treatment with ethylenetetracarbonitrile (TCNE) (Scheme 6).
- Trifonov, Latchezar S.,Orahovats, Alexander S.,Prewo, Roland,Heimgartner, Heinz
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p. 551 - 561
(2007/10/02)
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