Abstract
Photoredox catalyzed intermolecular couplings of alpha-bromochalcones to olefins have been developed. Employing 1 mol% of the iridium complex Ir(ppy)(3) as photocatalyst, vinyl radicals are generated from a-bromochalcones as the key intermediate, which efficiently engage in a formal [4+2] cyclization with various alkenes. The resulting 3,4-dihydronaphthalenes can be readily transformed to the ...
Abstract
Photoredox catalyzed intermolecular couplings of alpha-bromochalcones to olefins have been developed. Employing 1 mol% of the iridium complex Ir(ppy)(3) as photocatalyst, vinyl radicals are generated from a-bromochalcones as the key intermediate, which efficiently engage in a formal [4+2] cyclization with various alkenes. The resulting 3,4-dihydronaphthalenes can be readily transformed to the corresponding naphthalenes and further cyclized to 5H-benzo[c]fluorenes. Alternatively, Heck-type coupling products are obtained with sterically more hindered alkenes or allylated products if the alkene possesses a suitable leaving group in the allylic position.
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