Transition Metal Promoted Functionalization of Carboranes via Non-Traditional Metal─Carbon/Boron Bond

Zuowei Xie

Department of Chemistry, The Chinese University of Hong Kong

Shatin NT, Hong Kong, China

Carboranes constitute a class of structurally unique molecules with exceptionally thermal and chemical stabilities and the ability to hold various substituents. These properties have made them as useful basic units in boron neutron capture therapy agents, in supramolecular design, and in organometallic chemistry. On the other hand, such unique properties also make the functionalization of carboranes difficult. As a result, only limited methodologies for the derivatization of these clusters are known. In this connection, we have initiated a research program to actively explore transition metal-mediated or catalyzed carborane cage functionalization in the hope to develop new methodologies for assembling complex molecules from simple ones in a single operation. Subsequently, we reported transition metal-mediated reactions of o-carborynes (1,2-dehydro-o-carboranes) or 1,3-dehydro-o-carborynes with alkynes or alkenes for the synthesis of benzocarboranes or alkenylcarboranes [1-3]. In view of the different roles of early and late transition metals in the above reactions, we have recently developed three-component [2+2+2] cycloaddition of o-carboryne with alkene and alkyne or two different alkynes, affording a series of new functionalized carborane derivatives [4-5]. These results will be presented in this talk

Reference

[1] Qiu, Z.; Ren, S.; Xie, Z. Acc. Chem. Res. 2011, 44, 299.

[2] Qiu, Z.; Wang, S. R.; Xie, Z. Angew. Chem. Int. Ed. 2010, 49, 4649.

[3] Qiu, Z.; Xie, Z. J. Am. Chem. Soc. 2010, 132, 16085.

[4] Ren, S.; Qiu, Z.; Xie, Z. J. Am. Chem. Soc. 2012, 134, 3242.

[5] Ren, S.; Qiu, Z.; Xie, Z. Angew. Chem. Int. Ed. 2012, 51, 1010.