Synthesis of 9-Aryl-9,10-dihydrophenanthrenes by Domino [3+3] Annulation/Ring-Opening/Friedel-Crafts Alkylation Reactions of 1,3-Bis(trimethylsilyloxy)-1,3-butadienes with 3-Aroyl-5-aryl-4,5-dihydrofurans

Copper(I)-Catalyzed Direct Oxidative Annulation of 1,3-Dicarbonyl Compounds with Maleimides: Access to Polysubstituted Dihydrofuran Derivatives

An efficient annulation method for the synthesis of polysubstituted dihydrofurans from 1,3-dicarbonyl compounds and maleimides is described. The reactions can afford furo[2,3-c]pyrrole derivatives with satisfactory yields. The developed strategy realizes the direct oxidative double C(sp³)-H functionalization in the presence of copper(I) salts and 2-(tert-butylperoxy)-2-methylpropane. Meanwhile, this protocol features a mild reaction condition and simple catalytic system. A reaction mechanism involving a single electron oxidation is also proposed.