7300-29-0Relevant academic research and scientific papers
Lewis Basic Salt-Promoted Organosilane Coupling Reactions with Aromatic Electrophiles
Bandar, Jeffrey S.,Reidl, Tyler W.
supporting information, p. 11939 - 11945 (2021/08/20)
Lewis basic salts promote benzyltrimethylsilane coupling with (hetero)aryl nitriles, sulfones, and chlorides as a new route to 1,1-diarylalkanes. This method combines the substrate modularity and selectivity characteristic of cross-coupling with the practicality of a base-promoted protocol. In addition, a Lewis base strategy enables a complementary scope to existing methods, employs stable and easily prepared organosilanes, and achieves selective arylation in the presence of acidic functional groups. The utility of this method is demonstrated by the synthesis of pharmaceutical analogues and its use in multicomponent reactions.
Four-Selective Pyridine Alkylation via Wittig Olefination of Dearomatized Pyridylphosphonium Ylides
Dolewski, Ryan D.,Fricke, Patrick J.,McNally, Andrew
supporting information, p. 21283 - 21288 (2021/08/25)
Methods to synthesize alkylated pyridines are valuable because these structures are prevalent in pharmaceuticals and agrochemicals. We have developed a distinct approach to construct 4-alkylpyridines using dearomatized pyridylphosphonium ylide intermediates in a Wittig olefination-rearomatization sequence. Pyridine N-activation is key to this strategy, and N-triazinylpyridinium salts enable coupling between a wide variety of substituted pyridines and aldehydes. The alkylation protocol is viable for late-stage functionalization, including methylation of pyridine-containing drugs. This approach represents an alternative to metal-catalyzed sp2-sp3 cross-coupling reactions and Minisci-type processes.
Palladium-Catalyzed Arylation of Benzylic C-H Bonds of Azaarylmethanes with Aryl Sulfides
Gao, Ke,Yamamoto, Keita,Nogi, Keisuke,Yorimitsu, Hideki
supporting information, p. 2956 - 2960 (2017/10/06)
Benzylic C-H arylation of azaarylmethanes with aryl sulfides has been developed by using a Pd-NHC catalyst and an amide base. Various azaarylmethanes and aryl sulfides were involved in the reaction to afford the corresponding diarylmethanes in good to excellent yields. Moreover, triarylmethane synthesis was accomplished through iterative arylations of 2- or 4-methylpyridine with two different aryl sulfides.
Single-electron transmetalation in organoboron cross-coupling by photoredox/nickel dual catalysis
Tellis, John C.,Primer, David N.,Molander, Gary A.
, p. 433 - 436 (2014/08/05)
The routine application of Csp3-hybridized nucleophiles in cross-coupling reactions remains an unsolved challenge in organic chemistry. The sluggish transmetalation rates observed for the preferred organoboron reagents in such transformations are a consequence of the two-electron mechanism underlying the standard catalytic approach. We describe a mechanistically distinct single-electron transfer-based strategy for the activation of organoboron reagents toward transmetalation that exhibits complementary reactivity patterns. Application of an iridium photoredox catalyst in tandem with a nickel catalyst effects the cross-coupling of potassium alkoxyalkyl- and benzyltrifluoroborates with an array of aryl bromides under exceptionally mild conditions (visible light, ambient temperature, no strong base). The transformation has been extended to the asymmetric and stereoconvergent cross-coupling of a secondary benzyltrifluoroborate.
