The front cover picture illustrates the ring-opening cyclization of spiro[2.5]octane-4,8-dione and spiro[2.6]nonane-4,9-dione with phosphorus ylide, which acts as nucleophile to open the cyclopropane and is followed by an intramolecular C−C bond formation, affording [5.6]- and [5.7]-fused carbocyclic products, respectively. This protocol provides an efficient synthetic route for indanes and azulenes. Details can be found in the Research Article by Hisanori Nambu, Takayuki Yakura, and co-workers (Y. Onuki, K. Yamazaki. Y. Masuda, T. Yakura, H. Nambu, Adv. Synth. Catal. 2023, 365, 2536–2544; DOI: 10.1002/adsc.202300021).

中文翻译：

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封面图片：螺环丙烷与稳定的磷叶立德的开环环化：获得茚满和甘菊烯骨架（Adv. Synth. Catal. 15/2023）

封面图片说明了螺[2.5]辛烷-4​​,8-​​二酮和螺[2.6]壬烷-4,9-二酮与磷叶立德的开环环化反应，磷叶立德充当亲核试剂打开环丙烷，然后分子内CC键形成，分别提供[5.6]-和[5.7]-稠合碳环产物。该方案提供了茚满和甘菊环的有效合成路线。详细信息请参阅 Hisanori Nambu、Takayuki Yakura 及其同事的研究文章（Y. Onuki、K. Yamazaki. Y. Masuda、T. Yakura、H. Nambu、Adv. Synth. Catal . 2023 , 365 , 2536–2544；DOI：10.1002/adsc.202300021）。