Microwave-Promoted Copper-Free Sonogashira-Hagihara Couplings of Aryl Imidazolylsulfonates in Water
نویسندگان
چکیده
منابع مشابه
Sonogashira couplings of aryl bromides: room temperature, water only, no copper.
Cross-coupling reactions between lipophilic terminal alkynes and aryl bromides can be catalyzed by ligated Pd, in the absence of copper, in pure water at ambient temperatures. Small amounts of the nonionic amphiphile PTS assist by virtue of nanometer micelles formed spontaneously in an aqueous medium.
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Palladium on charcoal serves as an efficient and reusable solid supported catalyst for the Sonogashira coupling of aryl chlorides with terminal acetylenes in the presence of a bulky, electron-rich biphenyl type ligand (XPhos), without copper co-catalyst.
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Conditions for an efficient ligand-, copper-, and amine-free palladium-catalyzed Sonogashira reaction of aryl iodides and bromides with terminal alkynes have been developed. Critical to the success of this new protocol is the use of tetrabutylammonium acetate as the base. Noteworthy features of this method are room-temperature conditions and the tolerance of a broad range of functional groups i...
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ABSTRACT Copper-free, Pd/C-catalyzed, one-pot reaction of 2,3-dichloroquinoxaline with hydrazine hydrate, bromine, phenylacetylene, and a variety of aldehydes provides an efficient and direct method for the preparation of 1-aryl-4-(2-phenylethynyl)[1,2,4]triazolo[4,3-a]quinoxalines in water at 70 °C. This methodology involves the use of inexpensive reagents or catalysts, and thus permits a new ...
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ژورنال
عنوان ژورنال: Advanced Synthesis & Catalysis
سال: 2013
ISSN: 1615-4150
DOI: 10.1002/adsc.201200629