FeCl3-Mediated Oxidative Spirocyclization of Difluorenylidene Diarylethanes Leading to Dispiro fluorene-9,5'-indeno2,1-a indene10', 9''-fluorenes

摘要

A novel FeCl3-mediated oxidative spirocyclization for construction of a new class of di-spirolinked pi-conjugated molecules, dispiro fluorene-9,5'-indeno2,1-aindene-10',9''fluorenes (DSFIIFs), has been reported. The combination of FeCl3 with FeO(OH) triggered an unprecedented double one-electron oxidation of difluorenylidene diarylethanes to afford the corresponding dispirocycles in high yields. The highest fluorescence quantum yield was up to 0.94 in solution. This protocol is also applicable to the synthesis of the non-spirolinked dihydroindenoindenes.