Flavin Photocatalysts for Visible-Light [2+2] Cycloadditions: Structure, Reactivity and Reaction Mechanism

Varování

Publikace nespadá pod Filozofickou fakultu, ale pod Přírodovědeckou fakultu. Oficiální stránka publikace je na webu muni.cz.

Autoři	MOJR Viktor PITROVA Gabriela STRAKOVA Karolina PRUKALA Dorota BRAZEVIC Sabina SVOBODOVA Eva HOSKOVCOVA Irena BURDZINSKI Gotard SLANINA Tomáš SIKORSKI Marek CIBULKA Radek
Rok publikování	2018
Druh	Článek v odborném periodiku
Časopis / Zdroj	CHEMCATCHEM
Fakulta / Pracoviště MU	Přírodovědecká fakulta
Citace
www	Full Text
Doi	http://dx.doi.org/10.1002/cctc.201701490
Klíčová slova	cycloaddition; energy transfer; natural products; photochemistry; reaction mechanisms
Popis	New photocatalysts from the flavin family were found to mediate the [2+2] photocycloaddition reaction. 3-Butyl-10-methyl-5-deazaflavin (3a) and 1-butyl-7,8-dimethoxy-3-methylalloxazine (2e), if irradiated by visible light, were shown to allow an efficient (Phi approximate to 3-10%) intramolecular cyclisation of various types of substrates including substituted styrene dienes and bis(aryl enones), considered as electron-rich and electron-poor substrates, respectively, without any additional reagent. The versatility of the procedure was demonstrated by the cyclisation of photosensitive cinnamyl (E)-3-iodoallyl ether. Structure-activity studies found alloxazine 2e was more active than 7-monosubstituted (R = Cl, Br and MeO) alloxazines. The introduction of chlorine and bromine atom on the deazaflavin skeleton did not enhance the catalytic efficiency of 3a. A detailed electrochemical and spectroscopic study explains the reaction mechanism proceeding through energy transfer from the flavin excited triplet state to the diene followed by its cyclisation.
Související projekty:	CERIT Scientific Cloud