posted on 2021-11-29, 19:11authored byKailun Liang, Lijun Lu, Xing Liu, Dali Yang, Shengchun Wang, Yiming Gao, Hesham Alhumade, Hong Yi, Aiwen Lei
The
transition-metal-catalyzed [2 + 2 + 2] cyclotrimerization of
alkynes is one of the most straightforward routes for constructing
six-membered ring motifs. Although this strategy possesses high atom/step
economy and readily available substrates, the catalyst cycling is
the key problem. Herein, we disclosed a facile and efficient cobalt-catalyzed
cyclotrimerization of alkynes through electrochemical tools. Both
terminal and internal alkynes were tolerated under the mild reaction
conditions, affording the 1,2,4-trisubstituted and hexasubstituted
benzenes with high regioselectivity. Electrochemical redox accurately
tuned the valence of Co species to cycle the catalyst smoothly during
the whole reaction.