title: Nickel-mediated regioselective [2 + 2 + 2] cycloaddition of carboryne with alkynes.
abstract: Transition metal-benzyne complexes have found many applications in organic synthesis, mechanistic studies, and the synthesis of functional materials. In sharp contrast, the chemistry of transition metal-carboryne complexes, especially late transition metal complexes, is virtually unknown. This communication reports a novel nickel-mediated regioselective [2 + 2 + 2] cycloaddition reaction of carboryne with alkynes via the Ni-carboryne intermediate (eta2-C2B10H10)Ni(PPh3)2. Because of the bulkiness of the carborane moiety, a high regioselectivity was achieved in the reactions involving unsymmetrical alkynes. This work furnishes a novel method for the preparation of highly substituted benzocarboranes which are difficult to obtain by other methods.
authors.affiliation: Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territory, Hong Kong, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Deng
authors.forename: Hoi-Shan
authors.initials: HS
authors.lastname: Chan
authors.forename: Zuowei
authors.initials: Z
authors.lastname: Xie