Catalytic Generation of Borenium Ions by Cooperative B鈥揌 Bond Activation: The Elusive Direct Electrophilic Borylation of Nitrogen Heterocycles with Pinacolborane

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• 作者：Timo Stahl ; Kristine M眉ther ; Yasuhiro Ohki ; Kazuyuki Tatsumi ; Martin Oestreich
• 刊名：The Journal of the American Chemical Society
• 出版年：2013
• 出版时间：July 31, 2013
• 年：2013
• 卷：135
• 期：30
• 页码：10978-10981
• 全文大小：313K
• 年卷期：v.135,no.30(July 31, 2013)
• ISSN：1520-5126

文摘

The B鈥揌 bond of typical boranes is heterolytically split by the polar Ru鈥揝 bond of a tethered ruthenium(II) thiolate complex, affording a ruthenium(II) hydride and borenium ions with a dative interaction with the sulfur atom. These stable adducts were spectroscopically characterized, and in one case, the B鈥揌 bond activation step was crystallographically verified, a snapshot of the 蟽-bond metathesis. The borenium ions derived from 9-borabicyclo[3.3.1]nonane dimer [(9-BBN)₂], pinacolborane (pinBH), and catecholborane (catBH) allowed for electrophilic aromatic substitution of indoles. The unprecedented electrophilic borylation with the pinB cation was further elaborated for various nitrogen heterocycles.