Highly efficient syntheses of C-N axially chiral 1‐(ortho‐hydroxyaryl)uracil using a chiral auxiliary and a chiral base.
Highly efficient syntheses of C-N axially chiral 1‐(ortho‐hydroxyaryl)uracil using a chiral auxiliary and a chiral base.
复制标题
使用手性助剂和手性碱高效合成 C-N 轴向手性 1-(邻羟基芳基)尿嘧啶。
DOI：
10.1002/ajoc.201800247
复制
发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Murata. M.
中科院分区：
文献类型：
--
作者：
Hasegawa;F.;Yasukawa;Y.;Kawamura;K.;Tsuchikawa;H.;Murata. M.
我们在温和的条件下，通过手性助剂和手性碱的组合使用，实现了1 -芳基- 6 -氨基尿嘧啶的高度非对映选择性合成。我们发现(R)‐5‐烯丙基‐2‐氧沙环[3.3.0]oct‐1‐基是一个很好的手性助剂，当与奎尼丁结合时，有效地提供具有高非对构选择性的1‐芳基‐6‐氨基尿嘧啶（分离后可达98%）。奎尼丁中的手性醇部分似乎是在环化过程中实现立体选择性的关键。此外，在酸性条件下，手性助剂很容易从产物中去除，从而提供高对映体过量（高达96% ee）。该方法是产生C−N轴向手性的一种有效的非对映选择性环化方法。
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 %eeafter 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.