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Download fileAnnulative π‑Extension (APEX) of Heteroarenes with Dibenzosiloles and Dibenzogermoles by Palladium/o‑Chloranil Catalysis
journal contribution
posted on 2017-03-30, 14:41 authored by Kyohei Ozaki, Wataru Matsuoka, Hideto Ito, Kenichiro ItamiAnnulative π-extension
(APEX) reactions of heteroarenes are
described herein. A catalytic system comprising a cationic palladium
species and o-chloranil using dimethyldibenzosiloles
as π-extending agents enabled the extension of the π-system
of benzo[b]thiophenes. π-Extended dibenzofurans
and carbazoles could also be obtained from benzofuran and N-tosylindole, respectively, with dimethyldibenzogermole
as a germanium-based π-extending agent. Mechanistic investigations
indicated two possible reaction pathways involving carbopalladation-based
double C–H arylation of benzothiophene or formal cycloaddition/oxidation
cascades.