Novel synthesis of 3-iodo-ortho-carborane

A new and convenient route to 3-iodo-ortho-carborane was developed starting from thallium ortho-dicarbollide. This stable dicarbollide derivative can be isolated and purified thus avoiding undesirable by-product formation observed in a more conventional synthetic approach. Thallium dicarbollide readily reacts with boron triiodide in hexane to give the title compound in 70–80% yield and on a scale ranging from several milligrams to tens of grams of 3-iodo-ortho-carborane.