Progress in palladium-based catalytic systems for the sustainable synthesis of annulated heterocycles: a focus on indole backbones

BIOVERT+LDJA survey highlighting the most recent palladium catalytic systems produced and their performances for progress in direct synthesis of indole backbones by heterocarbocyclization of reactive substrates is provided. The discussion is developed in relation with the principles of sustainable chemistry concerning atom and mass economy. In this respect, the general convergent character of the syntheses is of particular interest (one-pot, domino, cascade or tandem reactions), and the substrates accessibility and reactivity, together with the final waste production, are also important. This critical review clearly indicates that the development of ligand chemistry, mainly phosphines and carbenes, in the last few decades gave a significant impetus to powerful functionalization of indoles at virtually all positions of this ubiquitous backbone (118 references)

Functionalized Tri- and Tetraphosphine Ligands as a General Approach for Controlled Implantation of Phosphorus Donors with a High Local Density in Immobilized Molecular Catalysts

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Transmission of spin-polarization by π-orbitals:an approach to assessing its effect on NMR spin-spin coupling and EPR hyperfine structure

Funding: We acknowledge the support from Slovak-French PHC Stefanik project “Spin Coupling Advanced Level Perception” (SCALP). OM, VM and JRA acknowledge the support from Slovak grant agencies APVV (grants No. SK-FR-19-0001 and APVV-19-0516) and VEGA (grant No. 2/0135/21). This work was also supported by the CNRS, the Université de Bourgogne, the Conseil Régional BFC (CHIMENE project), the PIA-excellence ISITE-BFC program (COMICS project) and the FEDER, which are all sincerely thanked.A new approach to assessing the effect of the transmission of spin-polarization by π-orbitals (π-TSP) is presented. In order to switch off the π-TSP effect, we artificially average the α- and β-densities of the valence π-orbitals when calculating the exchange–correlation contribution to the Fock matrix in the unrestricted Kohn–Sham framework. The π-TSP effect is then evaluated as the difference between the results obtained with switched-on and switched-off options. This approach is applied to estimate the π-TSP effect on the Fermi-contact contribution to spin–spin couplings and EPR hyperfine structure coupling constants. The π-TSP effect on the distribution of spin-density, spin–spin coupling pathways and pathways of EPR hyperfine couplings is demonstrated for benzene, naphthalene, 1,3,5,7,9-decapentaene and the 1,3,5,7,9-decapentaen-1-yl radical. The sign alternation of the spin-polarization transmitted by π-orbitals is explained in a theoretical framework based on perturbation theory. However, the delocalized nature of the π-system can interfere with the sign alternation in certain cases, two of which – the cyclobutadiene dication and the cyclooctatetraene dication – are examined, and an explanation for which is provided.PostprintPeer reviewe

Coordination chemistry of tetra- and tridentate ferrocenyl polyphosphines: an unprecedented [1,1'-heteroannular and 2,3-homoannular]-phosphorus-bonding framework in a metallocene dinuclear coordination complex

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Phosphine Ligands Based on the Ferrocenyl Platform: Advances in Catalytic Cross-Couplings

International audienceFerrocenyl skeletons tagged with a variety of donor atoms (metalloligands) have become popular in modern metal-catalyzed organic transformations, broadening the applications. Ferrocenylphosphines, such as 1′-bis(diphenylphosphino)ferrocene (dppf), have been widely used as metalloligands in academic and industrial research, motivating further investigation into novel ferrocenylphosphine ligands. The current review concentrated non-exhaustively on emblematic applications of different ferrocenylphosphine ligands in transition metal-catalyzed cross-coupling strategies. Initially, the stereochemical aspects of the ferrocenyl skeleton, nomenclature, and applications of chiral ferrocenyl phosphines in asymmetric synthesis are evoked. We simply classified ferrocenyl phosphine ligands, eventually further functionalized at cyclopentadienyl (Cp) ring, into three types based on the number of phosphine donors on the ferrocenyl backbone: monophosphine, bisphosphine, and polyphosphine ferrocenyl ligands. Furthermore, the use of hybrid monophosphinoferrocene type scaffolds (P, N)–, (P, O)–, (P, S–), (P, NHC)–, and (P, X)– (X is polar/hydrophilic like guanidium) in cross-coupling is evoked. The latest advances in the chemistry of symmetric achiral di- and polyphosphine ferrocene-based ligands related to metal-catalyzed bond-forming reactions (C–C, C–N, and C–O bonds) are discussed, with a special emphasis on consolidating all important work in this area. A cumulative table is provided in the end, with a focus on compiling significant work in this field. The general structure and electronic features and effects of ferrocenylphosphine ligands on the selectivity and activity in catalysis is also briefly evoked. The literature cut-off date was in general ending of 2020