Tracking the Process of a Solvothermal Domino Reaction Leading to a Stable Triheteroarylmethyl Radical: A Combined Crystallographic and Mass-Spectrometric Study.

A new free carbon radical was obtained in a microwave-assisted solvothermal reaction of the primary amine (1-methyl-1H-benzo[d]imidazol-2-yl)methanamine with FeCl3 ⋅6 H2 O in methanol at 140 °C. Through a combination of crystallography and electrospray ionization mass spectrometry, the reaction process was studied. The longest domino reaction includes 14 steps and forms up to 12 new covalent bonds (9 C-N and 3 C-C bonds) and 3 five-membered heterocycles. For the first time, the homolytic cleavage of a C-O bond was used to synthesize a triarylmethyl radical.