Reactions of Boron-Derived Radicals with Nucleophiles

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• 作者：Lauren E. Longobardi ; Pavel Zatsepin ; Roman Korol ; Lei Liu ; Stefan Grimme ; Douglas W. Stephan
• 刊名：Journal of the American Chemical Society
• 出版年：2017
• 出版时间：January 11, 2017
• 年：2017
• 卷：139
• 期：1
• 页码：426-435
• 全文大小：634K
• ISSN：1520-5126

文摘

Reactions of phenanthrenedione- and pyrenedione-derived borocyclic radicals, Cb>nb>Hb>8b>Ob>2b>B(Cb>6b>Fb>5b>)b>2b>^• (n = 14 (<b>1b>), 16 (<b>3b>)), with a variety of nucleophiles have been studied. Reaction of <b>1b> with P(t-Bu)b>3b> affords the zwitterion 3-(t-Bu)b>3b>PCb>14b>Hb>7b>Ob>2b>B(Cb>6b>Fb>5b>)b>2b> (<b>5b>) in addition to the salt [HP(t-Bu)b>3b>][Cb>14b>Hb>8b>Ob>2b>B(Cb>6b>Fb>5b>)b>2b>] (<b>6b>). In contrast, the reaction of <b>1b> with PPhb>3b> proceeds to give two regioisomeric zwitterions, 1-(Phb>3b>P)Cb>14b>Hb>7b>Ob>2b>B(Cb>6b>Fb>5b>)b>2b> (<b>7ab>) and 3-(Phb>3b>P)Cb>14b>Hb>7b>Ob>2b>B(Cb>6b>Fb>5b>)b>2b> (<b>7bb>), as well as the related boronic ester Cb>14b>Hb>8b>Ob>2b>B(Cb>6b>Fb>5b>) (<b>2b>). In a similar fashion, <b>3b> reacted with PPhb>3b> to give 3-(Phb>3b>P)Cb>16b>Hb>7b>Ob>2b>B(Cb>6b>Fb>5b>)b>2b> (<b>8ab>), 1-(Phb>3b>P)Cb>16b>Hb>7b>Ob>2b>B(Cb>6b>Fb>5b>)b>2b> (<b>8bb>), and boronic ester Cb>16b>Hb>8b>Ob>2b>B(Cb>6b>Fb>5b>) (<b>4b>). Reactions of secondary phosphines Phb>2b>PH and tBub>2b>PH with <b>3b> yield 3-(Rb>2b>PH)Cb>16b>Hb>7b>Ob>2b>B(Cb>6b>Fb>5b>)b>2b> (R = Ph (<b>9b>), t-Bu (<b>10b>)). The reaction of <b>1b> with N-heterocyclic carbene IMes afforded 3-(IMes)Cb>14b>Hb>7b>Ob>2b>B(Cb>6b>Fb>5b>)b>2b> (<b>11b>) and [IMesH][Cb>14b>Hb>8b>Ob>2b>B(Cb>6b>Fb>5b>)b>2b>] (<b>12b>), while the reactions with quinuclidine and DMAP afforded the species 3-(Cb>7b>Hb>13b>N)Cb>14b>Hb>7b>Ob>2b>B(Cb>6b>Fb>5b>)b>2b> (<b>13b>) and [H(NCb>7b>Hb>13b>)b>2b>][Cb>14b>Hb>8b>Ob>2b>B(Cb>6b>Fb>5b>)b>2b>] (<b>14b>), and the salt [9,10-(DMAP)b>2b>Cb>14b>Hb>8b>Ob>2b>B(Cb>6b>Fb>5b>)b>2b>][Cb>14b>Hb>8b>Ob>2b>B(Cb>6b>Fb>5b>)b>2b>] (<b>15b>), respectively. These products have been fully characterized, and the mechanism for the formation of these products is considered in the light of DFT calculations.