Transition-metal-mediated three-component cascade cyclization: selective cage B-C(sp2) coupling of carborane with aromatics and synthesis of carborane-fused tricyclics.
Zirconium/nickel comediated one-pot three-component cascade cyclization of carboryne, alkene, and 2-bromophenyltrimethylsilylacetylene has been achieved, leading to the formation of a series of C,C,B-substituted carborane-fused tricyclics. On the basis of experimental results, a plausible mechanism is proposed including [2 + 2 + 1] cross-cyclotrimerization followed by intramolecular direct selective cage B-C(sp(2)) coupling. This represents the first example of direct cage B-C(phenyl) coupling via cage B-H activation.
Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong , Shatin, New Territories, Hong Kong, China.
Yangjian
Y
Quan
Zaozao
Z
Qiu
Zuowei
Z
Xie