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The reported methods and data for the synthesis and reactivity of electron-deficient 3-vinylchromones containing electron-withdrawing­ groups at the exo-cyclic double bond are summarized and systematized for the first time. The main methods for obtaining these compounds are Knoevenagel condensation, Wittig reaction, and palladium-catalyzed cross-couplings. The most important chemical properties are transformations under the action of mono- and dinucleophiles, ambiphilic cyclizations, and cycloaddition reactions. The cross-conjugated and polyelectrophilic dienone system in 3-vinylchromones provides their high reactivity and makes these compounds valuable building blocks for the preparation of more complex heterocyclic systems. Chemical transformations of 3-vinylchromones usually begin with an attack of the C-2 atom and are accompanied by the opening of the pyrone ring followed by recyclization, in which the carbonyl group of chromone, an exo-double bond or a substituent on it can take part. The mechanisms of the reactions are discussed, the conditions for their implementation are described, and the yields of the resulting products are given. This review focuses on an analysis and generalization of the knowledge that has accumulated on the chemistry of electron-deficient 3-vinylchromones, mostly over the past 15 years.1 Introduction2 Synthesis of 3-Vinylchromones3 Reactions with Mononucleophiles4 Reactions with Dinucleophiles5 Ambiphilic Cyclization6 Cycloaddition Reactions7 Other Reactions8 Conclusion

Copper-catalyzed halide exchange reactions under very mild reaction conditions are described for the first time using a family of model aryl halide substrates. All combinations of halide exchange (I, Br, Cl, F) are observed using catalytic amounts of CuI. Strikingly, quantitative fluorination of aryl–X substrates is also achieved catalytically at room temperature, using common F– sources, via the intermediacy of aryl–CuIII–X species. Experimental and computational data support a redox CuI/CuIII catalytic cycle involving aryl–X oxidative addition at the CuI center, followed by halide exchange and reductive elimination steps. Additionally, defluorination of the aryl–F model system can be also achieved with CuI at room temperature operating under a CuI/CuIII redox pai We thank Prof. S. S. Stahl (Univ. of Wisconsin, Madison, WI) for fruitful comments and for early experiments conducted by A.C. in Stahl's lab. We acknowledge financial support from MICINN of Spain (CTQ2009-08464/BQU to M.C., CTQ2008-03077/BQU and CTQ2011-23156/BQU to M.S., Consolider-Ingenio CSD2010-00065, and Ph.D. grant to A.C.), European Research Council for Project ERC-2011-StG-277801 and the Catalan DIUE of the Generalitat de Catalunya (2009SGR637 to M.S., and a Ph.D. grant to M. Canta). X.R, MC., and MS. thank ICREA-Academia awards. We thank STR's from UdG for technical support, and we also acknowledge the Centre de Serveis Cientifics i Academics de Catalunya (CESCA) for partial funding of computer time

A novel synthetic approach for the synthesis of 3-substituted indoles by nucleophilic substitution of 3-bromo derivatives under phase transfer catalysis (PTC) was reported.

A well-defined macrocyclic aryl-CuIII complex (1) readily reacts with a series of R–SH, Ar–SH, Ar–SeH, and (RO)2(O)–PH (R = alkyl) nucleophiles to quantitatively afford the corresponding aryl alkyl thioethers, biaryl thioethers, biaryl selenide, and aryl dialkyl phosphonates, respectively. Competition experiments using bifunctional substrates revealed the important impact of lower pKa values in order to discriminate between functional groups, although other influencing parameters such as steric effects have been identified. The catalytic version of these reactions is achieved using aryl bromide and aryl chloride model substrates, affording C–S, C–Se, and C–P coupling compounds in excellent to moderate yields. Low-temperature UV–vis and NMR monitoring of the reactions of complex 1 with a variety of nucleophiles support the formation of a ground-state 1–nucleophile adduct. A mechanistic proposal for reaction of 1 with S-nucleophiles involving key nucleophile deprotonation and aryl-nucleophile reductive elimination steps is finally described We thank Dr. A. Casitas for fruitful discussions. We acknowledge financial support from the European Research Council for Project ERC-2011-StG-277801 to X.R., MICINN of Spain (CTQ2009-08464/BQU to M.C., CT2009-08328 to T.P., and Ph.D. FPI grant to M.F.), Consolider-Ingenio CSD2010-00065, and the Catalan DIUE of the Generalitat de Catalunya (2009SGR637). X.R. and M.C. acknowledge ICREA-Academia awards. We thank STR's from UdG for technical support