Activation of C-H Bonds of Alkyl- and Arylnitriles by the TaCl5 PPh3 Lewis Pair

作者：Rahman Md Mamdudur; Smith Mark D; Amaya Jose A; Makris Thomas M; Peryshkov Dmitry V^*

来源：Inorganic Chemistry, 2017, 56(19): 11798-11803.

DOI：10.1021/acs.inorgchem.7b01800

A new pathway of activation of C-H bonds of alkyl- and arylnitriles by a cooperative action of TaCl5 and PPh3 under mild conditions is reported. Coordination of nitriles to the highly Lewis acidic Ta(V) center resulted in an activation of their aliphatic and aromatic C-H bonds, allowing nucleophilic attack and deprotonation by the relatively weak base PPh3. The propensity of Ta(V) to form multiple bonds to nitrogen -containing ligands is an important driving force of the reaction as it led to a sequence of bond rearrangements and the emergence of, in the case of benzonitrile, a zwitterionic enediimido complex of Ta(V) through C=C double bond formation between two activated nitrile fragments. These transformations highlight the special role of the high-valent transition metal halide in substrate activation and distinguish the reactivity of the TaCl5-PPh3 system from both non-metal- and late transition metal-based frustrated Lewis pairs.

• 出版日期2017-10-2