A General and Convenient Palladium-Catalyzed Carbonylative Sonogashira Coupling of Aryl Bromides
作者:Xiao-Feng Wu、Helfried Neumann、Matthias Beller
DOI:10.1002/chem.201001864
日期:2010.10.25
Convenient carbonylations: An efficient methodology for the carbonylative Sonogashira reaction of aryl bromides has been developed (see scheme). Contrary to known procedures, inexpensive aryl bromides can be applied as substrates to give the desired compounds in moderate to good yields (47–88 %).
Base-mediated benzannulation of α-cyanocrotonates with ynones: facile synthesis of benzonitriles and fluorenes
作者:Maneesh Kumar Reddy Singam、Attunuri Nagireddy、Sridhar Reddy Maddi
DOI:10.1039/d0gc00608d
日期:——
Benzonitriles and cyanofluorenes have been rapidly obtained via the [3 + 3] benzannulation of readily available alkynones and α-cyanocrotonates using KOtBu as the only reagent and EtOH (and CO2) is the only by-product.
The metal-free oxidative alkene methylation/alkynylation of 1,4-enyn-3-ols with an organic peroxide as the methyl source has been developed, which provides straightforward and practical access to the challenging quaternary-carbon-containing but-3-yn-1-ones. The method is reasoned to go through methylation of functional alkenes utilizing dicumyl peroxide as the methylating reagent and subsequent intermolecular
Sunlight-Driven Decarboxylative Alkynylation of α-Keto Acids with Bromoacetylenes by Hypervalent Iodine Reagent Catalysis: A Facile Approach to Ynones
作者:Hui Tan、Hongji Li、Wangqin Ji、Lei Wang
DOI:10.1002/anie.201503479
日期:2015.7.13
A novel and practical decarboxylativealkynylation of α‐keto acids with bromoacetylenes is catalyzed by hypervalent iodine(III) reagents when irradiation by sunlight at room temperature. The product ynones are generated in good yields. Experiments show that results obtained with blue light (λ=450–455 nm) are comparable to those obtained when using sunlight. Mechanistic studies demonstrate that the
3-exo-dig cyclization with 1,2-alkynyl migration of 1,4-enynes with simple cycloalkanes was established, enabling C–C breaking and reconstruction to access a wide range of α-alkynyl ketones with generally good yields by FeCl2/di-tert-butyl peroxide (DTBP) as a catalytic oxidation system. Radical-induced C(sp3)–H functionalization of cycloalkanes was realized, leading to the direct formation of C(sp3)–C(sp3)