- T -BuONa-mediated direct C-H halogenation of electron-deficient (hetero)arenes
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An efficient halogenation of electron-deficient (hetero)arenes is described. The reaction utilizes common t-BuONa as a catalyst (for iodination) or a promoter (for bromination and chlorination), and perfluorobutyl iodide, CBr4 or CCl4 as the readily-available halogenating agents, respectively. The protocol features broad scope, high efficiency, mild conditions and gram scalability. An ionic pathway involving halogen bond formation and halophilic attack is proposed. The utility of the resulting iodinated heteroarenes is demonstrated in visible light-mediated Caryl-Caryl cross-coupling reaction.
- Liu, Xia,Zhao, Xin,Liang, Fushun,Ren, Baoyi
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supporting information
p. 886 - 890
(2018/02/19)
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- Method for preparing halogenated (hetero) aromatic hydrocarbons
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The invention relates to a method for preparing halogenated (hetero) aromatic hydrocarbons. The halogenated (hetero) aromatic hydrocarbons are prepared from cheap and easily available perfluorobutyl iodide, carbon tetrabromide and carbon tetrachloride as iodinated, brominated and chlorinated reagents respectively under the action of alkali catalysis (promotion). The method comprises the following steps: firstly, (hetero) aromatic hydrocarbons, a halogenated reagent and an inorganic base are placed in an organic solvent, stirred at room temperature and monitored with TLC until a substrate disappears, and the reaction is stopped; then, a reaction mixed solution is poured into water and extracted, an organic phase is dried, and the organic solvent is removed under reduced pressure; finally, silica-gel column chromatography is performed on a crude product, and a product is obtained. Purification can also be performed by recrystallization. The method has the advantages that the synthetic route is wide in substrate range, raw materials and reagents are cheap and easily available, operation is simple, conditions are mild, yield is high, energy consumption is reduced, the reaction route is safe, gram-grade preparation can be performed and the like.
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Paragraph 0039; 0040
(2018/03/24)
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- A new, mild one-pot synthesis of iodinated heterocycles as suitable precursors for N-heterocyclic carbene complexes
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The use of I2/AgOAc in dichloromethane constitutes a cheap, mild, and efficient method for the selective iodination of a variety of heterocycles. In a number of cases, this method provides superior yields to other literature methods and affords iodo-functionalized heterocycles that are suitable precursors for carbene complexes.
- Iglesias, Manuel,Schuster, Oliver,Albrecht, Martin
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experimental part
p. 5423 - 5425
(2010/11/02)
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- Synthesis of chiral pilocarpine analogues via a C-8 ketone intermediate.
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The synthesis of a chiral pilocarpine analogue 3 in which the lactone ring is replaced by an oxazolidinone and the bridging methylene group is in the ketone oxidation state has been accomplished. The utility of this compound as a key intermediate for the preparation of more complex structures was demonstrated by its reduction to two alcohol epimers and its reaction with a methylene ylide.
- Holden, Kenneth G,Mattson, Matthew N,Cha, Kyung Hoi,Rapoport, Henry
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p. 5913 - 5918
(2007/10/03)
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