Synthesis of Pentaalkyl-6-bromo-2,3,4,5-tetracarba-nido-hexaboranes(6)
Open Access
- 1 June 1996
- journal article
- Published by Walter de Gruyter GmbH in Zeitschrift für Naturforschung B
- Vol. 51 (6) , 859-864
- https://doi.org/10.1515/znb-1996-0616
Abstract
Peralkylated 2,3,4,5-tetracarba-mdo-hexaboranes(6) 1 react with boron tribromide, BBr3, via selective exchange of the alkyl substituent in 6-position to give the corresponding new 6- bromo derivatives 2 in quantitative yield. The 6-iodo derivatives 2(1) can be prepared in the same way using BI3. Treatment of the carbaboranes 2 with Li Et3BH leads to the 1,2,3,4,5- pentaalkyl-2,3,4,5-tetracarba-inido-hexaboranes(6) 3. 1,3,4,6-Tetraethyl-2,3,4,5-tetracarbaw do-hexaborane(6) 4 reacts with BBr3 via degradation of the carbaborane cage to give EtBBr2, and (Z)-1,4-bis [bis(dibromoboryl)]-3-hexene 5. A new bis(diethylboryl)-substituted dialkenyl(bromo)borane 8 was prepared, but attem pts failed to convert it into a 1-bromo- or 6-bromo-mdo-C4B2-carbaborane. Treatment of 1,1-dialkyl-3-diethylboryl-4-ethylstannoles 9 with a large excess of BBr3 also affords 5, whereas 6-bromo-l,3,4-triethyl-2,3,4.5-tetracarbamdo- hexaborane(6) 11 was isolated in low yield (3 (slight excess)Keywords
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