Herein, we present a radical cascade addition cyclization sequence to access quinoline‐based benzophosphole oxides from ortho‐alkynylated aromatic phosphine oxides using various aryl isonitriles as radical acceptors and inexpensive tert‐butyl‐hydroperoxide (TBHP) as a terminal oxidant in the presence of a catalytic amount of silver acetate. Alternatively, the same cascade can be realized through a sustainable photochemical approach utilizing 1,2,3,5‐tetrakis(carbazol‐9‐yl)‐4,6‐dicyanobenzene (4CzIPN) as an organic photocatalyst at room temperature. The introduced modular approach shows broad functional group tolerance and offers straightforward access to complex P,N‐containing polyheterocyclic arenes. These novel π‐extended benzophosphole oxides exhibit interesting photophysical and electrochemical properties such as absorption in the visible region, emission and reversible reduction at low potentials, which makes them promising for potential materials science applications. The photophysical properties can further be tuned by addition of external Lewis and Brønsted acids.

中文翻译：

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使用芳基异腈的热和光诱导自由基级联成环：一种制备喹啉衍生苯并磷氧化物的方法

在此，我们提出了一种自由基级联加成环化序列，使用各种芳基异腈作为自由基受体和廉价的叔丁基过氧化氢（TBHP）作为末端氧化剂，在存在催化量的醋酸银。或者，可以在室温下利用 1,2,3,5-四（咔唑-9-基）-4,6-二氰基苯（4CzIPN）作为有机光催化剂，通过可持续的光化学方法实现相同的级联。引入的模块化方法显示了广泛的官能团耐受性，并提供了直接获取复杂的含 P、N 多杂环芳烃的方法。这些新型π延伸苯并磷氧化物表现出有趣的光物理和电化学性质，例如可见光区域的吸收、发射和低电势下的可逆还原，这使得它们在潜在的材料科学应用中具有广阔的前景。通过添加外部路易斯酸和布朗斯台德酸可以进一步调节光物理性质。