Direct Access to Benzolactams and Benzolactones via Nickel Catalyzed Carbonylation with CO2
摘要:
A new nickel catalyzed cross‐electrophile coupling for accessing γ‐lactams (isoindolinones) as well as γ‐lactones (isobenzofuranones) via carbonylation with CO2 is documented. The protocol exploits the synergistic role of redox‐active Ni(II) complexes and AlCl3 as a CO2 activator/oxygen scavenger, leading to the formation of a wide range of cyclic amides and esters (28 examples) in good to high yields (up to 87%). A dedicated computational investigation revealed the multiple roles played by AlCl3. In particular, the simultaneous transient protection of the pendant amino group of the starting reagents and the formation of the electrophilically activated CO2‐AlCl3 adduct are shown to concur in paving the way for an energetically favorable mechanistic pathway.
Nickel-Catalyzed Cyclization of ortho-Iodoketoximes and ortho-Iodoketimines with Alkynes: Synthesis of Highly Substituted Isoquinolines and Isoquinolinium Salts
A convenient method for the synthesis of highly substituted isoquinolines and isoquinolinium salts by the nickel‐catalyzed cyclization of ortho‐haloketoximes and ‐ketimines, respectively, with alkynes is described. The reaction of ortho‐haloketoximes and various alkynes in the presence of [Ni(PPh3)2Br2] and zinc powder in a mixture of acetonitrile and tetrahydrofuran at 80 °C for 15 hours gave 1,3
Implication of a Silyl Cobalt Dihydride Complex as a Useful Catalyst for the Hydrosilylation of Imines
作者:Cassandre C. Bories、Marion Barbazanges、Etienne Derat、Marc Petit
DOI:10.1021/acscatal.1c03886
日期:2021.11.19
Here, we describe the formation and use of silyl cobalt (III) dihydride complexes as powerful catalysts for the hydrosilylation of a variety of imines starting from a low-valent well-defined cobalt (I) complex. The reaction is efficient at low catalyst loadings with a diverse range of imines bearing various protecting groups, as well as aliphatic ketimines and quinoline. Kinetics, DFT calculations