Tetrathienyl corannulene compounds showed highly sensitive photochromism with a large molar absorption coefficient and photocyclization quantum yield close to 1, although dithienyl phenanthrene compounds showed no photoreactivity. Such a high photoreactivity was rationalized by the predominance of the photoreactive atropisomers amplified by energy migration, and the curvature‐induced short distance between photoreactive carbons. More information can be found in the Research Article by M. Yamada, T. Kawai, and co‐workers (DOI: 10.1002/chem.202201286).

We have designed and synthesized photochromic tetrathienyl corannulene compounds, 1,2,7,8‐tetrakis(2‐methyl‐5‐phenylthiophen‐3‐yl)corannulene (1) and 1,2,7,8‐tetrakis(2,4‐dimethyl‐5‐phenylthiophen‐3‐yl)corannulene (2), by fusing two units of photochromic terarylene with a curved aromatic corannulene with a promising antenna effect. Compound 1 exhibited highly sensitive photoreactivity, with a large molar absorption coefficient of 8.2×104 M−1 cm−1 and practically photon‐quantitative photocyclization. On the other hand, a terarylene derivative with a planar aromatic phenanthrene, 9,10‐bis(2,4‐dimethyl‐5‐phenylthiophen‐3‐yl)phenanthrene (4) showed no photoreactivity. The reason for such a difference was attributed to the predominance of the photoreactive atropisomers amplified by energy migration, and the shortened distance between reactive carbons induced by the curved structure.

Pent-4-yn-1-ol was prepared with a high yield by the reaction of tetrahydrofurfuryl chloride with n-BuLi in t-BuOMe at 0 ˚C. Pent-4-en-1-ol was prepared with a high yield by either the reaction of tetrahydrofurfuryl chloride or tetrahydrofurfuryl bromide with lithium in tetrahydrofuran (THF) at temperatures from 0 ˚C to ambient temperature.