Diverse Reactivity of Zirconacyclocumulenes Derived from Coupling of Benzynezirconocenes with 1,3-Butadiynes towards Acyl Cyanides: Synthesis of Indeno2,1-bpyrroles or 3Cumulenones

摘要

The Group 4 metal complexes have attracted considerable attention owing to their fascinating structural features, their unique M-C bonding, and their unusual capacity to induce highly selective transformation reactions. One of the most extensively studied areas is the chemistry of diynes R(C≡C)2R and polyynes R(C≡C)_nR with metallocenes. An extensive investigation by Rosenthal and co-workers was performed using the metallocene source Cp2M(L)(η~2-Me3SiC≡CSiMe3) (M = Ti, L = -; M = Zr, L = THF; Cp = C5H5) as a low-valent metal equivalent. These studies revealed a variety of interesting reaction modes, such as complexation, C-C single-bond cleavage, and coupling reactions.