Photochemical reactivity of 1-substituted-1-aza-1,4-dienes promoted by electron-acceptor sensitizers. Di-pi-methane rearrangements and alternative reactions via radical-cation intermediates.
Irradiation of a series of beta,gamma-unsaturated imines, oxime acetates, and oxime methyl ethers, using 9,10-dicyanoanthrathene (DCA) or dicyanodurene (DCD) as electron acceptor sensitizers, affords the corresponding cyclopropanes resulting from 1-aza-di-pi-methane rearrangements via radical cations. In some cases, alternative reactions of these intermediates occur to yield nitriles, dihydroquinolines, dihydronaphthalene derivatives, and cycloaddition products. Some of these products result from reactions via alkene radical-cation intermediates while others arise by pathways involving imine radical-cation intermediates. The yields of products formed in these processes were significantly higher when DCD was used as electron-acceptor sensitizer instead of DCA.
Armesto
Diego
D
Departamento de Quimica Organica I, Facultad de Ciencias Quimicas, Universidad Complutense, 28040-Madrid, Spain. darmesto@quim.ucm.es
Ortiz
Maria J
MJ
Agarrabeitia
Antonia R
AR
Aparicio-Lara
Santiago
S
Martin-Fontecha
Mar
M
Liras
Marta
M
Martinez-Alcazar
M Paz
MP