Boomerang-shaped bipyrroles containing donor–acceptor units were obtained through a tandem palladium-mediated reaction consisting of a cyclization step, involving double C–H bond activation, and a double α-oxygenation. The latter reaction can be partly suppressed for the least reactive systems, providing access to α-unsubstituted boomerangs for the first time. These “α-free” systems are highly efficient fluorophores, with emission quantum yields exceeding 80% in toluene. Preliminary measurements show that helicene-like boomerangs may be usable as circularly polarized luminescent materials.

中文翻译：

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联吡咯回旋镖通过Pd介导的串联环化-加氧作用。控制反应的选择性和电子性能。

含有供体-受体单元的回旋镖形双吡咯是通过串联钯介导的反应获得的，该反应包括环化步骤，涉及双C–H键激活和双α-加氧。对于反应性最低的系统，可以部分抑制后者的反应，这是首次提供α-未取代的飞旋镖的入口。这些“无α”系统是高效的荧光团，在甲苯中的发射量子产率超过80％。初步测量结果表明，类螺旋烯回旋镖可以用作圆偏振发光材料。