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Syntheses, Structures, and Reactivity of Hexaborylbenzene Derivatives
Author(s) -
Ester Christian,
Maderna Andreas,
Pritzkow Hans,
Siebert Walter
Publication year - 2000
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/(sici)1099-0682(200006)2000:6<1177::aid-ejic1177>3.0.co;2-x
Subject(s) - chemistry , acetylene , adduct , pyridine , medicinal chemistry , diphenylacetylene , derivative (finance) , reactivity (psychology) , lewis acids and bases , benzene , yield (engineering) , catalysis , organic chemistry , medicine , materials science , alternative medicine , pathology , financial economics , economics , metallurgy
The hexaborylbenzene derivatives 2a and 2b have been obtained by transition metal catalyzed {[CpCo(CO) 2 ], [Co 2 (CO) 8 ], [Ni(cod) 2 ]} cyclotrimerization of bis(1,3,2‐benzodioxaborol‐2‐yl)acetylene ( 1a ) and bis[1,3,2‐(2,3‐naphtho)dioxaborol‐2‐yl]acetylene ( 1b ). Reaction of [Co 2 (CO) 8 ] with 1a yielded the bis(1,3,2‐dioxaborol‐2‐yl)dicobaltatetrahedrane derivative 3a , which has been subjected to X‐ray structure analysis. Reaction of stoichiometric amounts of 3a and diphenylacetylene was found to give the bis(boryl)tetraphenylbenzene derivative 4 , while 3a and mono(1,3,2‐benzodioxaborol‐2‐yl)acetylene ( 5 ) reacted to yield the tetraborylbenzene derivative 6 . AlMe 3 and AlEt 3 were found to react with 2a , b to furnish C 6 (BMe 2 ) 6 ( 7a ) and C 6 (BEt 2 ) 6 ( 7b ), respectively. With pyridine, the hexafunctional Lewis acid 7a formed the crystalline bis(pyridine) adduct C 6 (BMe 2 ) 6 ·(NC 5 H 5 ) 2 ( 8a ). Thermolysis of C 6 (BEt 2 ) 6 ( 7b ) resulted in the intramolecular elimination of ethane to give the 1,2,3,4‐bis(2′,3′‐dihydro‐1′,3′‐diborole)‐5,6‐bis(diethylboryl)benzene compound 9b . The molecular structure of the hexaborylbenzene pyridine adduct 8a has been determined by X‐ray structure analysis.