Cyclorearomatization process

These results, of course, contrast the significant effect of benzannelation in radical-anionic cycloaromatization reactions discussed above12 where not just the formation of a new aromatic cycle but also restoration of aromaticity in the previously existing cycle occurs at the same time in the cyclorearomatization process. 

Kovalenko and Alabugin reported that Cj-C cyclization of benzannelated enediynes with tetra-fluoropyridinyl (TFP) substituents at the terminal alkyne carbons forms indenes rather than fulvenes (Scheme 30.22). The radical/anionic Cj-Cj cyclization of enediynes represents a new type of cycloaromatization reaction—the cyclorearomatization process driven by rearomatization in the vicinity of the TS. This process is triggered via photoinduced electron transfer (PET) [35-38]. Expaimental work unambiguously established PET as the triggering event for the Cj-C cascade and the intermediacy of the second PET step in the indene-forming cascade [39]. Unlike the stable benzene product... 

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