Cobalt-catalyzed cyclization of benzamides with alkynes: a facile route to isoquinolones with hydrogen evolution
作者:Ramasamy Manoharan、Masilamani Jeganmohan
DOI:10.1039/c8ob01924j
日期:——
benzamides with alkynes assisted by an 8-aminoquinoline ligand in the presence of Co(OAc)2·4H2O and pivalicacid under an air atmosphere provided isoquinolone derivatives in good to excellent yields. In this reaction, the active Co(III) species is regenerated by the reaction of Co(I) species with pivalicacid under an air atmosphere with hydrogen evolution. The proposed mechanism was supported by competition
Through the oxidative addition of cobalt into the N-C(O) bond of phthalimide and the subsequent decarbonylation, we describe an efficient cobalt-catalyzed intermolecular decarbonylative carboamidation of alkynes. High regioselectivities have been achieved for unsymmetrical alkynes (including aryl-alkyl or aryl-aryl) to deliver polysubstituted isoquinolones. To facilitate step economy, a three-component
Transition metal catalyzed decarbonylation offers a distinct synthetic strategy for new chemical bond formation. However, the π‐backbonding between CO π* orbitals and metal center d‐orbitals impedes ligand dissociation to regenerate the catalyst under mild reaction conditions. Developed here is visible light induced rhodium catalysis for decarbonylativecoupling of imides with alkynes under ambient
作者:Lorena Capdevila、Tjark H. Meyer、Steven Roldán-Gómez、Josep M. Luis、Lutz Ackermann、Xavi Ribas
DOI:10.1021/acscatal.9b03620
日期:2019.12.6
allowed the selective synthesis of double-insertion aromatic homologation or alkyne monoannulation products by C–F/C–H activation. On the basis of the unambiguous crystallographic characterization of an unprecedented nine-membered nickelacyclic intermediate and extensive DFT studies, a plausible mechanistic rationale was established for the selective C–F activation and the chemodivergent catalysis.
A cobalt-catalyzed annulation of the C(sp2)–H/N–H bond of indoloamides with alkynes assisted by 8-aminoquinoline is reported for the synthesis of six-membered indololactams. The use of salicylaldehyde as the ligand is crucial for this transformation. The protocol has a broad scope for both alkynes and indoles. Preparing an active Co complex illustrates that salicylaldehyde plays a key role in the C–H