Mellerup Soren K, Li Cally, Radtke Julian, Wang Xiang, Li Quan-Song, Wang Suning
Department of Chemistry, Queen's University, Kingston, Ontario, K7L 3N6, Canada.
Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt, 60438, Frankfurt (Main), Germany.
Angew Chem Int Ed Engl. 2018 Jul 26;57(31):9634-9639. doi: 10.1002/anie.201803760. Epub 2018 May 9.
Chiral organoboron compounds with a chelate backbone and mesityl/heterocycle substituents (thienyl, furyl, and derivatives thereof) undergo a quantitative phototransformation that yields rare, chiral N,B,X-containing heterocycles, such as base-stabilized 1,2-thiaborinines and 1,2-oxaborinines. Boriranes were observed as intermediates in some of these transformations. The oxaborinines display further reactivity, generating 4a,12b-dihydrobenzo[h][1,2]oxaborinino[4,3-f]quinolines through a sequential conrotatory electrocyclization and a [1,5]-H shift. The N,B,X-containing heterocycles display strong blue-green to orange-red emission in the solid state. Combined DFT//CASP2T calculations suggest that a common biradical intermediate is responsible for the formation of these compounds as well as their interconversion.
具有螯合骨架和均三甲苯基/杂环取代基（噻吩基、呋喃基及其衍生物）的手性有机硼化合物会发生定量光转化，生成罕见的含手性N、B、X的杂环，如碱稳定的1,2-硫硼杂环戊二烯和1,2-氧硼杂环戊二烯。在其中一些转化过程中观察到硼杂环丙烷作为中间体。氧硼杂环戊二烯表现出进一步的反应活性，通过连续的顺旋电环化和[1,5]-H迁移生成4a,12b-二氢苯并[h][1,2]氧硼杂环戊二烯并[4,3-f]喹啉。含N、B、X的杂环在固态下呈现出强烈的蓝绿色至橙红色发射。结合密度泛函理论//完全活性空间自洽场二级微扰理论计算表明，一个常见的双自由基中间体负责这些化合物的形成及其相互转化。
