State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai, 200032, China.
Angew Chem Int Ed Engl. 2020 Jan 27;59(5):2039-2043. doi: 10.1002/anie.201912882. Epub 2019 Dec 17.
The stereodivergent iridium-catalyzed allylic alkylation and fluorination of acyclic ketones is described. α-Pyridyl-α-fluoroketones with vicinal tertiary and quaternary stereocenters were obtained in moderate to excellent yields and stereoselectivities. Distinct from known stereodivergent synthesis, for which two different chiral catalysts are required in general, herein we report a sequence-dependent stereodivergent synthesis. With only a single chiral Ir catalyst, all four possible stereoisomers of the products were prepared from the same starting materials by simply adjusting the sequence of asymmetric allylic alkylation and fluorination and varying the absolute configuration of the Ir catalyst.
本文描述了非环酮的立体发散性铱催化烯丙基烷基化和氟化反应。具有顺式三级和季立体中心的α-吡啶基-α-氟代酮以中等至优异的产率和立体选择性得到。与通常需要两种不同手性催化剂的已知立体发散性合成不同，本文报道了一种序列依赖性的立体发散性合成方法。仅使用单一手性 Ir 催化剂，通过简单地调整不对称烯丙基烷基化和氟化的顺序以及改变 Ir 催化剂的绝对构型，即可从相同的起始原料制备产物的所有四个可能的立体异构体。
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