Efficient and Practical Cross-Coupling of Arenediazonium Tetrafluoroborate Salts with Boronic Acids Catalyzed by Palladium(0)/Barium Carbonate (original) (raw)
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The synthesis of arylboronic acids and aryl trifluoroborates in a one-pot sequence by Ir-catalyzed borylation of arenes is reported. To prepare the arylboronic acids, the Ir-catalyzed borylation is followed by oxidative cleavage of the boronic ester with NaIO 4. To prepare the aryltrifluoroborate, the Ir-catalyzed borylation is followed by displacement of pinacol by KHF 2. These two-step sequences give products that are more reactive toward subsequent chemistry than the initially formed pinacol boronates.
European Journal of Organic Chemistry, 2007
Fifteen-membered triolefinic macrocyclic palladium(0) complex 1, (E,E,E)-1-ferrocenylsulfonyl-6,11-bis[(4-methylphenyl)sulfonyl]-1,6,11-triazacyclopentadeca-3,8,13-trienepalladium(0), is an active and recoverable catalyst for Suzuki-Miyaura cross-couplings between arenediazonium salts and potassium organotrifluoroborates. The reactions were performed under aerobic conditions at room temperature and
Synthesis and Minisci Reactions of Organotrifluoroborato Building Blocks
The Journal of Organic Chemistry, 2013
Copper-catalyzed borylation of a variety of organic halides with bis(pinacolato)diboron allows the preparation of diverse potassium organotrifluoroborates. The reactions are mild and general, providing access to a variety of interesting, boron-containing building blocks, including those containing piperidine, pyrrole, azetidine, tetrahydropyran and oxetane substructures. Representative Minisci reactions are reported for select examples. As a consequence of their successful and, thus, increasing use in a variety of reactions, the demand for new boron-containing building blocks is constantly growing. 1 Among them, organotrifluoroborates have been shown to be a valuable alternative to boronic acids owing to the increased stability conferred by the tetracoordinated boron atom. 2,3 In particular, the efficiency of the organotrifluoroborates in a broad range of reactions has been demonstrated, taking advantage of the reactivity of the boron-carbon bond, as well as reactions where the boron is retained. 4,5 Aliphatic potassium organotrifluoroborates can be easily obtained by simply treating appropriate organoboron precursors with potassium bifluoride (KHF 2) or KF in the presence of tartaric acid. 6 In general, the requisite organoborons can be accessed by different methods: 1) reaction of an organometallic (organomagnesium or organolithium) reagent with an electrophilic boron species BX 3 (X=Cl, F, OR); 7,8 2) hydroboration of alkenes; 9,10 or 3) borylation of alkanes by C-H bond activation. 11,12 Recently, much attention has been placed on the use of nucleophilic boron species and, in preference to the highly reactive boryllithiums or NHC-boranes, 13,14 activation of dibora compounds by a nucleophile was found to be a more efficient and useful synthetic protocol. 15,16 More precisely, copper(I)catalyzed reactions were particularly successful in the case of 1,4-additions to unsaturated carbonyl compounds, 17,18 and after the pioneering work on activated electrophiles by Miyaura, 19 the last year has witnessed the emergence of aliphatic borylation of halogenated substrates. Therefore, primary, secondary, and even tertiary alkylboronates have been prepared by Cu-, 20,21 Ni-, 22,23 or Pd-catalysis, 24 providing access to previously problematic targets. 25 Herein, we report the use of this method for the preparation of a variety of
Synthesis and Reactivity of Solid-Supported Organotrifluoroborates in Suzuki Cross-Coupling
Organic Letters, 2012
Solid-supported organotrifluoroborates were prepared in high yields by ion exchange with Amberlyst resins. The reactivity of solid supported aryltrifluoroborates was evaluated in Suzuki-Miyaura couplings with numerous aryl bromide partners. Electron rich and electron poor substituents were tolerated on both substrates, providing yields up to 90%. Examples of alkyl-, alkenyl-, alkynyl-and heteroaryltrifluoborates were also successfully cross-coupled to aryl halides.
International journal of engineering & technology, 2019
Hypervalent iodine compounds exhibit attractive features of low cost, mild and selective reagents in organic synthesis. These reagents serve as environmentally benign alternatives to toxic heavy-metal based oxidants and expensive organometallic catalysts. The practical and simple synthesis of unsymmetrical diaryl iodonium tetrafluoroborate salts is described. This synthetic method has allowed the production of isoxazole tetrafluoroborate salts from readily available aryl boronic acids without an extra anion exchange step in acceptable yields of 45% and 50%.
Applications of Fluorinated Aryl Boronates in Organic Synthesis
2020
Organoboron compounds are well known building blocks for many organic reactions. However, under basic conditions, polyfluorinated aryl boronic acid derivatives suffer from instability issues that are accelerated in compounds containing an ortho-fluorine group, which result in the formation of the corresponding protodeboronation products. Therefore, a considerable amount of research has focused on novel methodologies to synthesize these valuable compounds while avoiding the protodeboronation issue. This review summarizes the latest developments in the synthesis of fluorinated aryl boronic acid derivatives and their applications in cross-coupling reactions and other transformations. 4 Base-Free Pd-Catalyzed C-Cl Borylation of Fluorinated Aryl Chlorides 4.