Functionalisation of carboranes via five-membered metallacycles

Transition metals are often employed in multi-component reactions to assemble complex molecules with a metal centre. Such complexation of a metal centre to an unsaturated molecule significantly modifies its reactivity. However, achieving selectivity among different molecules remains challenging. 

Using transition metals Zr and Ni in cooperative action, the Joint Laboratory has recently achieved three-component cross-cyclotrimerisation of carboryne, alkyne/alkene and alkyne for the preparation of benzocarboranes, dihydrobenzocarboranes and dihydrofulvenocarboranes. These preliminary results provide a potential direction in designing new systems that display both high reactivity and predictable selectivity to increase the efficiency of assembling complex molecular architectures. The team aims to generate new organometallic synthons from carboranes, which could either react further with other unsaturated molecules or undergo cascade reactions to construct multifunctional carboranes, and explore the potential applications of these new functional carboranes as building blocks in organic materials. Through studying the reaction mechanism, the team hopes to not only enhance the knowledge about the reaction chemistry of metal-carborynes, but also develop new methodologies for making a new class of carborane derivatives.

The Shanghai-Hong Kong Joint Laboratory in Chemical Synthesis was established in 1999 jointly by the Chinese University of Hong Kong, The University of Hong Kong , and the Shanghai Institute of Organic Chemistry of the Chinese Academy of Sciences. It aims to train graduate students and to foster collaborative research efforts between the three participating institutions.