Base-induced photocyclization of 1,2-diaryl-1-tosylethenes. A mechanistically novel approach to phenanthrenes and phenanthrenoids.
The irradiation with UV light of a number of 1,2-diaryl-1-tosylstilbenes, in the presence of base, leads to the corresponding phenanthrenes and heterocyclic analogues. These results are consistent with a mechanism involving the base-induced elimination of p-toluenesulfinic acid from an intermediate 9-tosyl-4a,4b-dihydrophenanthrene, formed by photochemical cyclization of the starting 1,2-diaryl-1-tosylstilbenes. [reaction: see text]
Almeida
Jesús F
JF
Departamento de Química Orgánica y Unidad Asociada al CSIC, Universidad de Santiago de Compostela, 15782-Santiago de Compostela, Spain.
Castedo
Luis
L
Fernández
Dolores
D
Neo
Ana G
AG
Romero
Víctor
V
Tojo
Gabriel
G