We achieved a highly diastereoselective synthesis of 1‐aryl‐6‐aminouracils, which are C−N atropisomeric compounds, through the combined use of a chiral auxiliary and a chiral base under mild conditions. We found that the (R)‐5‐allyl‐2‐oxabicyclo[3.3.0]oct‐1‐yl group is a good chiral auxiliary that, when combined with quinidine, efficiently affords 1‐aryl‐6‐aminouracils with high diastereoselectivity (up to 98 % ee after isolation). The chiral alcohol moiety in quinidine appears to be crucial for achieving stereoselectivity during cyclization. Furthermore, the chiral auxiliary was easily removed from the product under acidic conditions to provide the atropisomer with high enantiomeric excess (up to 96 % ee). The developed method is an efficient diastereoselective‐cyclization method for the generation of C−N axial chirality.

中文翻译：

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使用手性助剂和手性碱高效合成CN轴向手性1-（邻羟基芳基）尿嘧啶

通过在温和条件下结合使用手性助剂和手性碱，我们实现了非芳香族选择性合成1–芳基-6-氨基尿嘧啶（C–N阻转异构化合物）的方法。我们发现（R）-5-烯丙基-2-氧杂双环[3.3.0] oct-1-基是一个很好的手性助剂，与奎尼丁结合使用时，可以有效地提供具有高非对映选择性的1-芳基-6-氨基尿嘧啶（高达ee的98％ 隔离后）。奎尼丁中的手性醇部分似乎对于在环化过程中实现立体选择性至关重要。此外，在酸性条件下容易从产物中除去手性助剂，从而为阻转异构体提供高对映体过量（至多96％ee）。所开发的方法是一种有效的非对映选择性环化方法，用于生成CN轴向手性。