INFIQC, Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA Córdoba, Argentina.
Org Biomol Chem. 2021 Dec 22;20(1):228-239. doi: 10.1039/d1ob01673c.
A synthetic approach towards the 6-benzo[]chromene ring under visible light and transition-metal-free conditions has been developed. Benzochromenes are synthesized from the corresponding (2-halobenzyl) phenyl ethers or (2-halophenyl) benzyl ethers using KOBu in dimethyl sulfoxide (DMSO) at room temperature (rt) and blue light-emitting diodes (LEDs) as the light source. This methodology replaces the use of ligands or additives, high temperatures and toxic solvents. The photostimulated reaction exhibits very good tolerance to different functional groups and 5-dibenzo[,]chromenes are also effectively obtained. An electron donor-acceptor complex formed by the dimsyl anion and (2-halobenzyl) phenyl ethers was found and it induces the ET as the initial step in the photocyclization reaction. Furthermore, in order to explain the regiochemical outcome of this reaction, a theoretical analysis was performed using DFT methods.
一种在可见光和无过渡金属条件下合成 6-苯并[]色烯环的方法已经开发出来。通过使用 KOBu 在二甲亚砜（DMSO）中在室温（rt）和蓝色发光二极管（LED）下从相应的（2-卤代苄基）苯基醚或（2-卤代苯基）苄基醚合成苯并色烯。该方法取代了配体或添加剂、高温和有毒溶剂的使用。光激发反应对不同的官能团具有很好的耐受性，并且也有效地获得了 5-二苯并[,]色烯。发现二甲基砜阴离子和（2-卤代苄基）苯基醚形成的电子给体-受体复合物，并诱导 ET 作为光环化反应的初始步骤。此外，为了解释该反应的区域化学结果，使用 DFT 方法进行了理论分析。
