- C-F activation for C(sp2)-C(sp3) cross-coupling by a secondary phosphine oxide (SPO)-nickel complex
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A secondary phosphine oxide (SPO)-nickel catalyst allowed the activation of otherwise inert C-F bonds of unactivated arenes in terms of challenging couplings with primary and secondary alkyl Grignard reagents. The C-F activation is characterized by mild reaction conditions and high levels of branched selectivity. Electron-rich and electron-deficient arenes were suitable electrophiles for this transformation. In addition, this strategy also proved suitable to heterocycles and for the activation of C-O bonds under slightly modified conditions.
- Müller, Valentin,Ghorai, Debasish,Capdevila, Lorena,Messinis, Antonis M.,Ribas, Xavi,Ackermann, Lutz
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supporting information
p. 7034 - 7040
(2020/09/15)
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- Terminal-Selective Functionalization of Alkyl Chains by Regioconvergent Cross-Coupling
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Hydrocarbons are still the most important precursors of functionalized organic molecules, which has stirred interest in the discovery of new C?H bond functionalization methods. We describe herein a new step-economical approach that enables C?C bonds to be constructed at the terminal position of linear alkanes. First, we show that secondary alkyl bromides can undergo in situ conversion into alkyl zinc bromides and regioconvergent Negishi coupling with aryl or alkenyl triflates. The use of a suitable phosphine ligand favoring Pd migration enabled the selective formation of the linear cross-coupling product. Subsequently, mixtures of secondary alkyl bromides were prepared from linear alkanes by standard bromination, and regioconvergent cross-coupling then provided access to the corresponding linear arylation product in only two steps.
- Dupuy, Stéphanie,Zhang, Ke-Feng,Goutierre, Anne-Sophie,Baudoin, Olivier
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p. 14793 - 14797
(2016/11/23)
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- Nickel-catalyzed alkylative cross-coupling of anisoles with grignard reagents via C-O bond activation
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We report nickel-catalyzed cross-coupling of methoxyarenes with alkylmagnesium halides, in which a methoxy group is eliminated. A wide range of alkyl groups, including those bearing β-hydrogens, can be introduced directly at the ipso position of anisole derivatives. We demonstrate that the robustness of a methoxy group allows this alkylation protocol to be used to synthesize elaborate molecules by combining it with traditional cross-coupling reactions or oxidative transformation. The success of this method is dependent on the use of alkylmagnesium iodides, but not chlorides or bromides, which highlights the importance of the halide used in developing catalytic reactions using Grignard reagents.
- Tobisu, Mamoru,Takahira, Tsuyoshi,Morioka, Toshifumi,Chatani, Naoto
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p. 6711 - 6714
(2016/06/14)
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- Decalins
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Decalins of the formula STR1 wherein ring A is aromatic or a trans-1,4-disubstituted cyclohexane ring; R2 is methyl, --CH2 R', --OR', --CO--R', --CN, --COOH, --CO--OR', --CO--SR' or --O--CO--R'; R1 is hydrogen, methyl, --CH2 R, --OR or --CH2 OR, or when R2 is methyl, --CH2 R', --OR' or --CO--R', R1 also can be --CN, --COOH, --CO--OR, --CO--SR or --O--CO--R; R and R' each are alkyl; and R1 and R2 each have up to 12 carbon atoms and together have at most 14 carbon atoms, their racemates and optically active antipodes, are described. Liquid crystalline mixtures comprising Compound I as well as their use in electro-optical devices also are disclosed.
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