In this report, we introduce a new strategy for controlling the stereochemistry in Ugi adducts. Instead of controlling stereochemistry directly during the Ugi reaction we have attempted to stereodefine the chiral center at the peptidyl position through the post-Ugi functionalization. In order to achieve this, we chose to study 2-oxo-aldehyde-derived Ugi adducts many of which partially or fully exist in the enol form that lacks the aforementioned chiral center. This in turn led to their increased nucleophilicity as compared to the standard Ugi adducts. As such, the stereocenter at the peptidyl position could be installed and stereodefined through the reaction with a suitable electrophile. Towards this end, we were able to deploy an asymmetric cinchona alkaloid-promoted electrophilic fluorination producing enantioenriched post-Ugi adducts fluorinated at the peptidyl position.

中文翻译：

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通过金鸡纳生物碱促进的亲电氟化控制2-氧-醛衍生的Ugi加合物的立体化学。

在本报告中，我们介绍了一种控制Ugi加合物中立体化学的新策略。代替直接在Ugi反应中控制立体化学，我们尝试通过Ugi后官能化在肽基位置立体定义手性中心。为了实现此目的，我们选择研究2-氧-醛-衍生的Ugi加合物，其中许多部分或完全以缺少上述手性中心的烯醇形式存在。与标准的Ugi加合物相比，这又导致它们的亲核性增加。这样，可以通过与合适的亲电试剂反应来安装和确定肽基位置的立体中心。为此，