Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences , Nanyang Technological University , Singapore 637371 , Singapore.
Org Lett. 2019 Feb 15;21(4):1202-1206. doi: 10.1021/acs.orglett.9b00182. Epub 2019 Feb 6.
A visible-light-induced photocatalytic intramolecular cyclization of 2-(1-arylvinyl)benzaldehydes is reported. The reaction is promoted in the presence of an Ir photocatalyst and an amine base at room temperature under the irradiation of blue LEDs, affording 10-methylanthracen-9(10 H)-one derivatives in moderate to good yields with tolerance to various functional groups. A series of mechanistic experiments suggest that the reaction proceeds via energy transfer from the excited Ir photocatalyst to the substrate to generate a diradical, which then undergoes 1,5-hydrogen shift, 6π electrocyclization, and aromatization leading to the cyclic product.
报告了可见光诱导的 2-(1-芳基乙烯基)苯甲醛的分子内环化反应。在室温下，在 Ir 光催化剂和胺碱的存在下，蓝光 LED 的照射下促进了该反应，以中等至良好的收率得到了 10-甲基蒽-9(10H)-酮衍生物，对各种官能团具有耐受性。一系列的机理实验表明，反应是通过从激发态 Ir 光催化剂到底物的能量转移来进行的，生成双自由基，然后经历 1,5-氢迁移、6π电环化和芳构化，生成环状产物。
