O-Substituted isocyanates (O-isocyanates) have rarely been used in organic synthesis, given their tendency to undergo side reactions (e.g., trimerization). Herein, we show that masked (blocked) O-isocyanate precursors allow one-pot or cascade reaction sequences featuring base-catalyzed substitution with 2-iodoanilines and 2-iodobenzylamines followed by copper-catalyzed cyclization, to form benzimidazolones and 3,4-dihydroquinazolin-2(1H)-ones. This work shows that O-isocyanates can serve as efficient building blocks for the synthesis of hydroxylamine-containing heterocycles.

中文翻译：

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O取代异氰酸酯的催化取代/环化序列：1-烷氧基苯并咪唑酮和1-烷氧基-3,4-二氢喹唑啉-2（1 H）-ones的合成

考虑到O-取代的异氰酸酯（O-异氰酸酯）易于发生副反应（例如三聚）的趋势，因此很少用于有机合成中。在这里，我们表明，被掩盖的（封闭的）O-异氰酸酯前体允许一锅或级联反应序列，其特征在于用2-碘苯胺和2-碘苄胺进行碱催化的取代，然后进行铜催化的环化反应，形成苯并咪唑酮和3,4-二氢喹唑啉-2（1 H）-ones。这项工作表明，O-异氰酸酯可以作为合成含羟胺杂环的有效构件。