A visible-light-mediated radical tandem cyclization of ortho-isocyano-α-bromo cinnamates to 2-substituted indole-3-glyoxylates is achieved by formation of both C–C/C–S and C–O bonds. The reaction proceeds through a hitherto unprecedented bromine- or methoxy-group-promoted umpolung back electron transfer from an α-carbonyl radical to the photocatalyst. This method allows preparation of diverse 2-arylated
Facile Access to 2-Arylindolines and 2-Arylindoles by Microwave-Assisted Tandem Radical Cyclization
作者:Oliver Reiser、Inga Prediger、Torsten Weiss
DOI:10.1055/s-2008-1067154
日期:2008.7
A new route providing access to 2-arylindoles has been developed. The synthesis consists of a tin-mediated tandem radical cyclization of appropriate precursors to form 2,3-disubstituted dihydroindoles, which in turn are oxidized to yield the corresponding 2-arylindoles. The reactions proceed smoothly under microwave irradiation, furnishing the desired products in good yields.