Abstract

The reaction of N-(2,4-dinitrophenyl)pyridinium-d₅ chloride with N-(4-methylphenyl)piperazine in refluxing ethanol led to the ring opening of the pyridinium-d₅ ring to afford the conjugated triene with a penta-2,4- dienylideneammonium-d₅ (PDA-d₅) group, namely, triene-D^a₂D^b₂D^c. The reaction of triene-D^a₂D^b₂D^c with 1,1,2,2- tetracyanoethylene (TCNE) or 7,7,8,8-tetracyanoquinodimethane (TCNQ) in methanol (MeOH) and N,N-dimethylformamide (DMF) selectively activated the C-D bonds at the 2- and 4-positions of the PDA-d₅ group. The present selective C-D/C-H exchange reaction may have applications in the development of new organocatalyzed coupling reactions

Keywords: Organocatalyst, C-D/C-H exchange, conjugated triene, pyridinium salt, TCNE, TCNQ.

Graphical Abstract