Synthesis of carborane-fused carbo- and heterocycles via zirconacyclopentane intermediates

A variety of carborane-fused carbo- and heterocycles were prepared in good to high isolated yields via the reaction of carborane-fused zirconacyclopentane with a series of substrates such as S-8, Se, Te, CO, XylNC, MeOOC-CH=N-2, PhPCl2, (Bu2SnCl2)-Bu-n and Me2GeCl2. However, it was found that the Zr-C bond in the zirconacyclopentane did not show any reactivity towards PhBCl2, PhCN and PhCH-NPh. This approach represents a promising route to functionalized carboranes that are difficult to access by conventional methods.