1595-11-5Relevant articles and documents
Photoredox-Assisted Reductive Cross-Coupling: Mechanistic Insight into Catalytic Aryl-Alkyl Cross-Couplings
Paul, Avishek,Smith, Mark D.,Vannucci, Aaron K.
, p. 1996 - 2003 (2017/02/26)
Here, we describe a photoredox-assisted catalytic system for the direct reductive coupling of two carbon electrophiles. Recent advances have shown that nickel catalysts are active toward the coupling of sp3-carbon electrophiles and that well-controlled, light-driven coupling systems are possible. Our system, composed of a nickel catalyst, an iridium photosensitizer, and an amine electron donor, is capable of coupling halocarbons with high yields. Spectroscopic studies support a mechanism where under visible light irradiation the Ir photosensitizer in conjunction with triethanolamine are capable of reducing a nickel catalyst and activating the catalyst toward cross-coupling of carbon electrophiles. The synthetic methodology developed here operates at low 1 mol % catalyst and photosensitizer loadings. The catalytic system also operates without reaction additives such as inorganic salts or bases. A general and effective sp2-sp3 cross-coupling scheme has been achieved that exhibits tolerance to a wide array of functional groups.
Cross-coupling reactions through the intramolecular activation of Alkyl(triorgano)silanes
Nakao, Yoshiaki,Takeda, Masahide,Matsumoto, Takuya,Hiyama, Tamejiro
supporting information; scheme or table, p. 4447 - 4450 (2010/08/19)
(Figure Presented) Cross-Si-ing the Jordan: Cross-coupling reactions of 2-(2-hydroxyprop-2-yl)phenylsubstituted alkylsilanes with a variety of aryl halides proceed in the presence of palladium and copper catalysts. The use of K3PO4 base allows for highly chemoselective alkyl coupling with both primary and secondary alkyl groups (Alk).
Ligand exchange as the first irreversible step in the nickel-catalyzed cross-coupling reaction of grignard reagents
Yoshikai, Naohiko,Matsuda, Hirokazu,Nakamura, Eiichi
supporting information; experimental part, p. 15258 - 15259 (2009/03/12)
Mechanistic studies of the Ni-catalyzed cross-coupling reaction of Grignard reagents through analysis of kinetic isotope effects and theoretical calculations indicated that the product-to-substrate ligand exchange process is the first irreversible step and affects the turnover efficiency and selectivity of the reaction. On the other hand, the oxidative addition step is the first irreversible step in Pd catalysis. This finding has useful implications for the development of efficient Ni catalysis and also illustrates the importance of the catalyst turnover step that has so far received less attention than subsequent catalytic steps. Copyright