29619-42-9Relevant articles and documents
Sonogashira coupling and cyclization reactions on alumina: A route to aryl alkynes, 2-substituted-benzo[b]furans and 2-substituted-indoles
Kabalka, George W.,Wang, Lei,Pagni, Richard M.
, p. 8017 - 8028 (2001)
A solventless, microwave-enhanced Sonogashira coupling reaction of aromatic iodides with terminal alkynes on potassium fluoride doped alumina in the presence of palladium powder, cuprous iodide, and triphenylphosphine has been developed. The reaction can be utilized to prepare aryl alkynes in excellent yields. The coupling of o-iodophenol with terminal alkynes leads to the formation 2-substituted-benzo[b]furans. Whereas the coupling of o-iodoanilines with terminal alkynes generates indole products. An in situ desilylation reaction was also developed.
"canopy Catalysts" for Alkyne Metathesis: Molybdenum Alkylidyne Complexes with a Tripodal Ligand Framework
Copéret, Christophe,Fürstner, Alois,Gordon, Christopher P.,Hillenbrand, Julius,Leutzsch, Markus,N?thling, Nils,Wille, Christian,Yiannakas, Ektoras
supporting information, p. 11279 - 11294 (2020/07/13)
A new family of structurally well-defined molybdenum alkylidyne catalysts for alkyne metathesis, which is distinguished by a tripodal trisilanolate ligand architecture, is presented. Complexes of type 1 combine the virtues of previous generations of silanolate-based catalysts with a significantly improved functional group tolerance. They are easy to prepare on scale; the modularity of the ligand synthesis allows the steric and electronic properties to be fine-tuned and hence the application profile of the catalysts to be optimized. This opportunity is manifested in the development of catalyst 1f, which is as reactive as the best ancestors but exhibits an unrivaled scope. The new catalysts work well in the presence of unprotected alcohols and various other protic groups. The chelate effect entails even a certain stability toward water, which marks a big leap forward in metal alkylidyne chemistry in general. At the same time, they tolerate many donor sites, including basic nitrogen and numerous heterocycles. This aspect is substantiated by applications to polyfunctional (natural) products. A combined spectroscopic, crystallographic, and computational study provides insights into structure and electronic character of complexes of type 1. Particularly informative are a density functional theory (DFT)-based chemical shift tensor analysis of the alkylidyne carbon atom and 95Mo NMR spectroscopy; this analytical tool had been rarely used in organometallic chemistry before but turns out to be a sensitive probe that deserves more attention. The data show that the podand ligands render a Mo-alkylidyne a priori more electrophilic than analogous monodentate triarylsilanols; proper ligand tuning, however, allows the Lewis acidity as well as the steric demand about the central atom to be adjusted to the point that excellent performance of the catalyst is ensured.
Preparation and Reactions of Mono- and Bis-Pivaloyloxyzinc Acetylides
Tüllmann, Carl Phillip,Chen, Yi-Hung,Schuster, Robin J.,Knochel, Paul
supporting information, p. 4601 - 4605 (2018/08/09)
Mono-pivaloyloxyzinc acetylide and bis-pivaloyloxyzinc acetylide were selectively prepared from ethynylmagnesium bromide in quantitative yields. These zinc reagents readily underwent Negishi cross-couplings with (hetero)aryl iodides or bromides as well as subsequent Sonogashira cross-couplings. 1,3-Dipolar cycloadditions of these zinc acetylides with benzylic azides produced zincated and bis-zincated triazoles which were trapped with several electrophiles. An opposite regioselectivity compared to the Cu-catalyzed click-reactions was observed.
One-Pot Domino Synthesis of Diarylalkynes/1,4-Diaryl-1,3-diynes by [9,9-Dimethyl-4,5-bis(diphenylphosphino)xanthene] (Xantphos)–Copper(I) Iodide–Palladium(II) Acetate-Catalyzed Double Sonogashira-Type Reaction
Qiu, Shaozhong,Zhang, Caiyang,Qiu, Rui,Yin, Guodong,Huang, Jinkun
, p. 313 - 321 (2018/01/15)
The low loading combination of the complex [9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene] (Xantphos)copper(I) iodide and simple ligand-free palladium(II) acetate was found to be efficient for the domino synthesis of diarylalkynes by the reaction of aryl halides with trimethylsilylethynylene or bis(trimethylsilyl)acetylene in a single-step procedure. The unsymmetrical diarylalkynes can be obtained through a one-pot two-step approach. The reactions of aryl bromides with 1,4-bis(trimethylsilyl)butadiyne also furnished the corresponding 1,4-diaryl-1,3-diynes in a similar fashion. This route to diarylalkynes and 1,4-diaryl-1,3-diynes is complementary to previously reported synthetic procedures. (Figure presented.).
