Synthesis and characterization of 3-chloropropyl-substituted o-carboranes: Crystal structures of 1,2-(1,3-propanediyl)-o-carborane, 1-(3-chloropropyl)-o- carborane and 1,2-bis(3-chloropropyl)-ocarborane

摘要

The reactions of the lithio-o-carborane Li_2C_2B _(10)H_(10) with ClCH_2CH_2CH_2Br were studied under various conditions. While the main product is the known exo-polyhedrally cyclized 1,2- (1,3-propanediyl)-o-carborane (2), the expected 3-chloropropyl-substituted carborane products 1- (ClCH_2CH _2CH_2)C_2B_(10)H_(11) (3) and 1,2-(ClCH _2CH_2CH_2)_2C_2B _(10)H_(10) (4) can be obtained in a total yield of 22%. In the presence of CuCl, the same reaction proceeded rather slowly and gave compound 3 and bis(o-carborane) (5) in small yields, with the recovery of the starting o-C_2B_(10)H_(12). Compounds 2 - 4 were characterized by means of IR and NMR spectroscopy and mass spectrometry, as well as by single-crystal X-ray diffraction.