New formylating agents - Preparative procedures and mechanistic investigations

The reactivity of new formylating agents related to formamide has been investigated both experimentally and theoretically. The reaction in 1,2-dichloroethane between tris(diformylamino)methane (2) and several arenes, catalyzed by AlCl3 or BCl3, was shown to proceed in good yields to afford the corresponding para-substituted aldehydes. The nature of the active electrophilic species was also investigated theoretically, Thus, the relative stability of the O- and N-protonated forms, as well as those of AlCl3 adducts, of several formylating agents - diformamide, triformamide, N,N,N',N'-tetraformylhydrazine, and tris(diformylamino) methane-were determined in the gas phase and in water or DCE by means of DFT calculations at the B3LYP/6-311++G(d,p) level, the solvents being modeled-with the IPCM method. The amide oxygen atom in all cases appeared to be the most basic site, both in the Bronsted and Lewis sense, constituting a first step towards the understanding of the mechanism of this reaction.