Laboratory of Catalysis and Organic Synthesis, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, EPFL SB ISIC LCSO, BCH 4306, 1015, Lausanne, Switzerland.
Angew Chem Int Ed Engl. 2019 Sep 23;58(39):13880-13884. doi: 10.1002/anie.201907060. Epub 2019 Aug 21.
We report an oxidative ring-opening strategy to transform acyl, sulfonyl or carbamate protected aminocyclopropanes into 1,3-dielectrophilic carbon intermediates bearing a halide atom (Br, I) and a N,O-acetal. Replacing the alkoxy group of the N,O-acetal can be achieved under acidic conditions through an elimination-addition pathway, while substitution of the halides by nucleophiles can be done under basic conditions through a S 2 pathway, generating a wide range of 1,3-difunctionalized propylamines. A proof of concept for asymmetric induction was realized using a chiral phosphoric acid (CPA) as catalyst, highlighting the potential of the method in enantioselective synthesis of important building blocks.
我们报告了一种氧化开环策略，可将酰基、砜基或氨基甲酸酯保护的氨基环丙烷转化为带有卤素原子（Br、I）和 N,O-缩醛的 1,3-双亲电性碳中间体。在酸性条件下，通过消除-加成途径可以实现 N,O-缩醛的烷氧基取代，而在碱性条件下通过 S N 2 途径可以实现卤素的取代，生成广泛的 1,3-二官能化丙胺。使用手性磷酸（CPA）作为催化剂实现了不对称诱导的概念验证，突出了该方法在手性重要砌块合成中的潜在应用。
