Abstract
In this work, a photoinduced synthesis of isoxazolidine-fused isoquinolin-1-ones and
3,4-dihydro[1,2]oxazino[2,3-b]isoquinolin-10(2H)-one from alkyne-tethered N-alkoxybenzamides is reported. The gram-scaled synthesis and structural elaboration
of isoxazolidine-fused isoquinolin-1-ones are also realized. The reaction is promoted
by an equimolar amount of tetrabutylammonium chloride, under metal- and catalyst-free
conditions. In the reaction, it is believed that the alkyne-tethered N-alkoxybenzamide
starting materials serve as photosensitizers, and the photoexcited substrate induces
the formation of a chloro radical. The N-radical results from hydrogen atom abstraction
by the chloro radical at the N–H bond of the substrates.
Key word
photoinduced - metal-free - N-radical - quinolin-1-ones - cascade cyclization
