259244-78-5Relevant academic research and scientific papers
Heterodisubstituted 1,10-dicarba-closo-decaboranes from substituted nido-carborane precursors
Janousek, Zbynek,Kaszynski, Piotr
, p. 3517 - 3526 (1999)
Mono- and heterodisubstituted 1,10-dicarba-closo-decaboranes 1 have been prepared from substituted nido-carboranes 3 and by carboxylation and arylation of 1-alkyl-p-carboranes. Thermal dehydrogenation followed by skeletal rearrangement of 3 furnished 1 in modest yields. Alkyl substituents tolerated the high temperature process whereas the 4-bromophenyl derivative 1d underwent partial disproportionation. The preparation of the nido-carboranes 3 was accomplished in three ways: by acetylene insertion to nonaborane 6, modified Plesek oxidation of dicarbaundecaborate anions 4 with Fe(III), and a new homogenous oxidation of 4 using gaseous SO2. The newly developed homogenous deboronation with SO2 appears to be more efficient than the classical Plesek oxidation especially for highly lypophilic carboranes. The overall yields for the preparation of substituted p-carboranes 1 using the three methods from 6 or 4 are about 8% and 14%, respectively. Elsevier Science Ltd.
