Carboranes dicarbaboranes

A convenient route to three-carbon carboranes is the hydroboration of an alkyne with a preformed dicarbaborane. For example, reaction of ethyne (or propyne) with arachno-4,5-C2B7Hi3 (70) in hexane at 120°C gives a mixture of tri- and tetra-carbaboranes, e.g. (71), (72), (73), (74) in modest yield. Access to other... 

The chemistry of the eleven-vertex nido tricarbaboranes (tricarbollides) is, in contrast to that of the dicarbollides1 one of the youngest areas of carborane chemistry. It was as late as in 1995 when the first representatives of this family were reported.2 Essentially, there are two synthetic routes leading to tricarbollide compounds cyanide and isonitrile methods.3 The cyanide method is based on a room-temperature reaction between the dicarbaborane... 

The last bond network in Figure 3.7 illustrates the only localized bond option open to a tervalent atom required to bond to six neighbors, which it can do only by use of three 3c-2e bonds. Not surprisingly, carbon atoms are not normally found in connectivity six sites in carboranes. The only such site among infraicosahedral closo dicarbaboranes, the unique site in C2B9H11, is... 

A convenient route to three-carbon carboranes is the hydroboration of an alkyne with a preformed dicarbaborane. For example, reaction of ethyne (or propyne) with arachno-... 

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