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|Title:||Photochemical reactions of tetraorganoborate salts: Electron transfer-mediated photoreductions and alkylations and di-pi-borate rearrangements|
|Author(s):||Kropp, Michael Andrew|
|Doctoral Committee Chair(s):||Schuster, Gary B.|
|Department / Program:||Chemistry|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Abstract:||The photochemical reaction of sodium borohydride and methyltriphenylborate with halo-substituted cyanonaphthalenes has been studied. The reaction leads to photo-dehalogenation in high yield. Sodium borohydride was also found to react photochemically with dicyanonaphthalene, leading to reduction products. These reactions are proposed to occur through an initial electron transfer step.
Photoalkylations of aryl ketones with alkyltriphenylborates has also been studied. The excited state of the ketone reacts with the borate via electron transfer, yielding addition and reduction products.
The direct irradiation of alkyl and aryl borates was investigated. Photolysis of trans-$\beta$-styryltriphenylborate leads to the formation of trans-1,1,2,3-tetraphenylboratirane. Similarly, photolysis of (phenylethynyl)triphenylborate leads to the formation of 1,1,2,3-tetraphenylboratirene. Both of these compounds are believed to be formed via a di-$\pi$-borate rearrangement. These are the first examples of a tetravalent, anionic boron atom contained in a three-membered ring to be isolated and characterized. Both compounds show intriguing properties.
Irradiation of (2-phenylcyclopropyl)dimethylphenylborate showed evidence for the formation of a boratetane, a tetravalent boron atom in a four-membered ring.
|Rights Information:||Copyright 1990 Kropp, Michael Andrew|
|Date Available in IDEALS:||2011-05-07|
|Identifier in Online Catalog:||AAI9114303|