Rhodium-catalyzed intramolecular [4 + 2] cycloadditions of alkynyl halides.
TL;DR: Cationic rhodium(I)-catalyzed intramolecular [4 + 2] cycloadditions of diene-tethered alkynyl halides were found to occur in good yields and could be transformed into a variety of products that are difficult or impossible to obtain via directcycloaddition.
About: This article is published in Organic Letters.The article was published on 2005-11-22. It has received 45 citations till now. The article focuses on the topics: Cycloaddition & Intramolecular force.
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TL;DR: This Account highlights some of the recent progress on the development of efficient and practical synthetic methods involving haloalkyne reagents in the laboratory and in others around the world, which showcase the synthetic power of haloalkynes for rapid assembly of complex molecular structures.
Abstract: Inspired by the need for green and sustainable chemistry, modern synthetic chemists have been seeking general and practical ways to construct complex molecules while maximizing atom economy and minimizing synthetic steps. Over the past few decades, considerable progress has been made to fulfill these goals by taking advantage of transition metal catalysis and chemical reagents with diverse and tunable reactivities. In recent years, haloalkynes have emerged as powerful and versatile building blocks in a variety of synthetic transformations, which can be generally conceived as a dual functionalized molecules, and different reaction intermediates, such as σ-acetylene-metal, π-acetylene-metal, and halovinylidene-metal complexes, can be achieved and undergo further transformations. Additionally, the halogen moieties can be retained during the reaction processes, which makes the subsequent structural modifications and tandem carbon-carbon or carbon-heteroatom bond formations possible. As a consequence, impressive effort has been devoted to this attractive area, and some elegant work has been done over the past several years. This Account highlights some of the recent progress on the development of efficient and practical synthetic methods involving haloalkyne reagents in our laboratory and in others around the world, which showcase the synthetic power of haloalkynes for rapid assembly of complex molecular structures. The focus is primarily on reaction development with haloalkynes, such as cross-coupling reactions, nucleophilic additions, and cycloaddition reactions. The designed approaches, as well as serendipitous observations, will be discussed with special emphasis placed on the mechanistic aspects and the synthetic utilities of the obtained products. These transformations can lead directly to heteroatom-containing products and introduce structural complexity rapidly, thus providing new strategies and quick access to a wide range of functionalized products including many synthetically useful conjugated cyclic and acyclic structures that have potential applications in natural product synthesis, materials science, and drug discovery. Importantly, most of these protocols allow multiple bond-forming events to occur in a single operation, thereby offering opportunities to advance chemical synthesis and address the increasing demands for economical and sustainable synthetic methods. We anticipate that a deep understanding of the properties of haloalkyne reagents and the underlying working mechanism can lead to the development of novel catalytic systems to answer the unsolved challenges in haloalkyne chemistry, which, in turn, may be also instructive for other research areas. We hope this Account will help to provide a guideline for researchers who are interested in this fertile area.
217 citations
196 citations
146 citations
Patent•
17 Jul 2006
TL;DR: In this paper, the authors provide compounds of the general Formulae (I) through general Formula (VIII), as well as compositions, including pharmaceutical compositions, comprising a subject compound.
Abstract: The embodiments provide compounds of the general Formulae (I) through general Formula (VIII), as well as compositions, including pharmaceutical compositions, comprising a subject compound. The embodiments further provide treatment methods, including methods of treating a hepatitis C virus infection and methods of treating liver fibrosis, the methods generally involving administering to an individual in need thereof an effective amount of a subject compound or composition.
136 citations
TL;DR: The thermally promoted cycloaddition between alkynyliodides and nitrile oxides is reported, which offers excellent regioselectivity and a broad scope with respect to both the iodoalkynes and chloro-oximes.
Abstract: The thermally promoted cycloaddition between alkynyliodides and nitrile oxides is reported. The process offers excellent regioselectivity and a broad scope with respect to both the iodoalkynes and chloro-oximes. Further functionalization of the highly decorated iodoisoxazole motifs can be achieved via Suzuki cross-coupling.
70 citations
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TL;DR: The phytochemical remains of the seven-membered ring formation are still under investigation, but it is clear that the polymethine content of the ring is lower than previously thought, suggesting that it is more likely to be a mixture of 22π and 32σ.
Abstract: 5.7. [32π + 32σ] Cycloadditions 74 5.8. [44π + 22π] Cycloadditions 75 6. Seven-Membered Ring Formation 78 6.1. [44π + 32σ] Cycloadditions 78 6.2. [52π+2σ + 22π] Cycloadditions 79 7. Eight-Membered Ring Formation 79 7.1. [22π + 22π + 22π + 22π] Cycloadditions 80 7.2. [44π + 22π + 22π] Cycloadditions 80 7.3. [44π + 44π] Cycloadditions 81 7.4. [66π + 22π] Cycloadditions 83 8. Ten-Membered Ring Formation 85 9. Conclusion and Remarks 87
1,456 citations
TL;DR: A practical cross-coupling of amides with alkynyl bromides using catalytic CuSO(4).5H(2)O and 1,10-phenanthroline is described here and provides a general entry for syntheses of ynamides including various new sulfonyl and heteroaromatic amine substituted ynamide.
275 citations
256 citations
TL;DR: The cross-coupling reaction is applied to a one-pot synthesis of the corresponding unsymmetrical diarylethynes from (trimethylsilyl)ethyne via sequential Sonogashira-Hagihara and the present cross-Coupling reactions using two different aryl triflates.
Abstract: Reaction of 1-trimethylsilylalkyne with copper(I) chloride in a polar solvent, DMF, at 60 degrees C under an aerobic conditions smoothly undergoes homo-coupling to give the corresponding symmetrical 1,3-butadiynes in 70-99% yields. In addition, (arylethynyl)trimethylsilanes are found to couple with aryl triflates and chlorides in the presence of Cu(I)/Pd(0) (10 mol %/5 or 10 mol %) cocatalyst system to give the corresponding diarylethynes in 49-99% yields. The cross-coupling reaction is applied to a one-pot synthesis of the corresponding unsymmetrical diarylethynes from (trimethylsilyl)ethyne via sequential Sonogashira-Hagihara and the present cross-coupling reactions using two different aryl triflates. The reactions of (arylethynyl)trimethylsilanes with aryl(chloro)ethynes in the presence of 10 mol % of CuCl also yield the corresponding unsymmetrical 1,3-butadiynes in 43-97% yields.
228 citations
TL;DR: A copper-catalyzed new C-N bond formation involving a sp-hybridized carbon is described here leading to a facile entry for syntheses of chiral ynamides, which should have a significant impact on the future development of synthetic methodologies employing ynamide.
Abstract: A copper-catalyzed new C−N bond formation involving a sp-hybridized carbon is described here leading to a facile entry for syntheses of chiral ynamides. This direct N-alkynylation of amides should have a significant impact on the future development of synthetic methodologies employing ynamides.
197 citations