Nickel-Catalyzed Intramolecular 1,2-Aryl Migration of Mesoionic Carbenes (iMICs).

ABSTRACT: Intramolecular 1,2-Dipp migration of seven mesoionic carbenes (iMIC^Ar ) 2?a-g (iMIC^Ar =ArC{N(Dipp)}₂ CHC; Ar=aryl; Dipp=2,6-iPr₂ C₆ H₃ ) under nickel catalysis to give 1,3-imidazoles (IMD^Ar ) 3?a-g (IMD^Ar =ArC{N(Dipp)CHC(Dipp)N}) has been reported. The formation of 3 indicates the cleavage of an N-C_Dipp bond and the subsequent formation of a C-C_Dipp bond in 2, which is unprecedented in NHC chemistry. The use of 3 in accessing super-iMICs (5) (S-iMIC=ArC{N(Dipp)N(Me)C(Dipp)}C) has been shown with selenium (6), gold (7), and palladium (8) compounds. The quantification of the stereoelectronic properties reveals the superior ?-donor strength of 5 compared to that of classical NHCs. Remarkably, the percentage buried volume of 5 (%V_bur =45) is the largest known amongst thus far reported iMICs. Catalytic studies show a remarkable activity of 5, which is consistent with their auspicious stereoelectronic features.

SUBMITTER: Merschel A 

PROVIDER: S-EPMC7898293 | biostudies-literature | 2021 Feb

REPOSITORIES: biostudies-literature