Rhodium‐Catalyzed Cascade Synthesis of Benzofuranylmethylidene‐Benzoxasiloles: Elucidating Reaction Mechanism and Efficient Solid‐State Fluorescence
作者:Tomoya Namba、Yoshihiro Hayashi、Susumu Kawauchi、Yu Shibata、Ken Tanaka
DOI:10.1002/chem.201800381
日期:2018.5.17
in the solution state (φF=69–87 %) by introduction of electron‐donating alkyl and phenyl groups on two phenoxy groups. In the powder state, 4‐methyl‐ and 4‐methoxy‐phenoxy derivatives exhibited efficient blue fluorescence (φF=52 % and 46 %, respectively). Especially, the 4‐methylphenoxy derivative was thermally stable, and exhibited strong narrow‐band fluorescence in the film state (blue, φF=95 %)
通过阳离子铑(I)/双键配合物催化双(2-乙炔基苯酚)硅烷的级联环异构化反应,开发了一种新的合成途径,用于合成高荧光的苯并呋喃基甲叉基苯并三唑,涉及1,2-硅和1,3-碳(炔)的迁移氧环化。本发明的合成仅需三个步骤,从市售的二氯二异丙基硅烷开始,这明显短于我们先前的合成(八个步骤,由市售的氯二异丙基硅烷开始)。理论计算阐明了上述级联环异构化的机理。该反应是通过亚甲基铑的形成而不是通过直接的1,2-硅迁移而引发的,而是通过空前的逐步1形成的,5-硅迁移,然后由脱芳构的烯丙基铑配合物形成C-Si键形成环化。随后的1,3-碳(炔烃)迁移导致η3-烯基/炔丙基-铑络合物,然后通过与阳离子铑(I)络合物的π键(炔烃)活化进行氧环化,得到苯并呋喃基甲叉基苯并xasilole产物。这样获得的benzofuranylmethylidenebenzoxasiloles的结构-荧光特性的关系进行了调查,结果发