Synthesis of terminal-biradical compounds consisting of two N-oxyl groups connected with conjugated π-systems
Terminal-biradical compounds 1 having two N-oxyl groups connected with conjugated π-systems were synthesized by (1) addition of magnesium acetylide to 4-oxo-TEMPO, followed by dehydration, or (2) cross-coupling between acetylene and vinyl triflate derived from 4-oxo-TEMPO.