The photocyclization of diarylethenes toward polycyclic aromatic hydrocarbons and analogs has been well-documented. However, stiff-stilbene was reported to be inactive, and examples of photocyclization-induced deamination remain unknown. Here, we report that ortho-(N,N-dimethylamino)-stiff-stilbene (1a) undergoes efficient photocyclization-induced deamination, forming the dicyclopenta-fused phenanthrene (DCPP) with good yield (65%) under anaerobic conditions. The relative reactivities of stiff-stilbenes with different o-amino substituents (1b–1g) or with an o-methoxy (1h) group, and those of o-(N,N-dimethylamino)stilbenes (2a and 2aMe), provide insights into the substituent and structural effects.

中文翻译：

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邻位二烷基氨基取代的二苯乙烯的厌氧光环化

二芳基乙烯光环化生成多环芳烃及其类似物已有充分记录。然而，据报道，刚性二苯乙烯是无活性的，并且光环化诱导的脱氨基的例子仍然未知。在这里，我们报道了邻-( N,N-二甲基氨基)-硬-二苯乙烯( 1a )在厌氧条件下经历了有效的光环化诱导脱氨，形成双环五稠合菲( DCPP )，产率良好(65%)。具有不同邻氨基取代基 ( 1b–1g ) 或邻甲氧基 ( 1h ) 基团的硬二苯乙烯的相对反应性，以及邻-( N,N-二甲基氨基)二苯乙烯（2a和2aMe）的相对反应性，提供了见解分为取代基和结构效应。