C 2 -Symmetric Rhenacyclobutadienes: Key Intermediates in Re(V) Alkylidyne-Catalyzed Alkyne Metathesis Reactions - Long Yiu Tsang; Mingxu Cui; Lam Cheung Kong; Jie Huang; Wan Chak Lee; Herman H. Y. Sung; Ian D. Williams; Zhenyang Lin; Guochen Jia (Journal of the American Chemical Society, 2026)