Department of Chemistry, Boston College , Chestnut Hill, Massachusetts 02467, United States.
Org Lett. 2014 Jun 20;16(12):3340-3. doi: 10.1021/ol501362w. Epub 2014 Jun 11.
The first example of catalytic B-H activation of azaborines leading to a new family of stilbene derivatives through dehydrogenative borylation is reported. Ten 1,2-azaborine-based BN isosteres of stilbenes have been synthesized using this method, including a BN isostere of a biologically active stilbene. It is demonstrated that BN/CC isosterism in the context of stilbenes can lead to significant changes in the observed photophysical properties such as higher quantum yield and a larger Stokes shift. Direct comparative analysis of BN stilbene 3g and its carbonaceous counterpart 6g is consistent with a stronger charge-transfer character of the excited state exhibited by 3g in which the 1,2-azaborine heterocycle serves as a better electron donor than the corresponding arene.
首次报道了通过脱氢硼化反应使硼氮杂环戊二烯（azaborines）催化 B-H 活化，从而得到一系列新型二苯乙烯衍生物的实例。该方法合成了十种基于 1,2-氮硼杂环戊二烯的二苯乙烯 BN 等排体，包括一种具有生物活性的二苯乙烯 BN 等排体。结果表明，二苯乙烯中 BN/CC 等排性会导致观察到的光物理性质发生显著变化，例如量子产率更高和斯托克斯位移更大。对 BN 二苯乙烯 3g 和其相应的碳取代物 6g 的直接对比分析表明，3g 中激发态的电荷转移特性更强，其中 1,2-氮硼杂环戊二烯杂环的电子给体能力强于相应的芳烃。
