Photochemical electrocyclization and leaving group expulsion with a naphthothiophene-2-carboxanilide linked to a chromophore
作者:Lingzi Li、Gilbert N. Ndzeidze、Mark G. Steinmetz
DOI:10.1016/j.tet.2018.11.013
日期:2019.1
naphthiothiophene-2-carboxanilide bearing a leaving group at the C-3 position undergoes efficient electrocyclic ring closure and leaving group expulsion upon direct photolysis. The reaction occurs in the triplet excited state and can be sensitized by thioxanthone. Thioxanthone as chromophore can also be covalently attached to amide nitrogen by a trimethylene linker, and the photoreaction is equally efficient
在C-3位置带有离去基团的萘噻吩噻吩-2-甲酰苯胺经过有效的电环闭环,直接光解后会将离去基团排出。该反应以三重激发态发生并且可以被噻吨酮敏化。噻吨酮作为生色团也可以通过三亚甲基接头与酰胺氮共价连接,并且光反应同样有效。淬火研究表明,由于噻吨酮生色团的快速放热能量转移,三重态激发主要位于萘噻吩部分。cri啶黄染料能够在450 nm处敏化光反应,但是在这种情况下量子产率很低。