An Arylation Strategy to Propargylamines: Catalytic Asymmetric Friedel–Crafts‐type Arylation Reactions of C‐Alkynyl Imines |
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Authors: | Yingcheng Wang Liang Jiang Long Li Jun Dai Dan Xiong Prof?Dr Zhihui Shao |
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Institution: | Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, School of Chemical Science and Technology, Yunnan University, Kunming, China |
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Abstract: | The first arylation strategy for the synthesis of enantioenriched propargylamines is disclosed. This approach, which is complementary to previous alkynylation and alkylation strategies, involves a C(sp2)?C(sp3) bond formation, and is based on the first asymmetric Friedel–Crafts‐type arylation reaction of C‐alkynyl imines. Asymmetric Friedel–Crafts reactions with electron‐deficient phenols, a longstanding unsolved challenge, have thus been realized for the first time, enabled by the combination of our recently introduced C‐alkynyl N‐Boc‐protected N,O‐acetals as electrophiles and chiral phosphoric acids as catalysts. The synthetic utility of the resulting structurally diverse and polyfunctional chiral propargylamines was demonstrated by a series of selective transformations, including controlled reduction of the alkynyl group and iterative cross‐couplings. |
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Keywords: | alkynyl imines arylation Brø nsted acids Friedel– Crafts reaction propargylamines |
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