Copper-catalyzed asymmetric allylic alkylation of racemic inert cyclic allylic ethers under batch and flow conditions. Issue 16 (3rd April 2023)

• Record Type: Journal Article
• Authors: Li, Jun; Song, Xiao; Wang, Yan; Huang, Junrong; You, Hengzhi; Chen, Fen-Er
• Is Part Of: Chemical science. Volume 14:Issue 16(2023)
• Page Start: 4351
• Page End: 4356
• Publication Date: 2023-04-03
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d3sc00127j
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : The Cu-catalyzed AAA reactions employing challenging racemic inert cyclic allylic ethers with sterically hindered Grignard reagents have been disclosed under batch and flow conditions. Abstract : Highly enantioselective Cu-catalyzed asymmetric allylic alkylation of racemic inert cyclic allylic ethers is accomplished in this work. The use of Grignard reagents in combination with BF3 ·OEt2 and CuBr·SMe2 /L2 is the key to enable employment of long-challenging low reactive allylic substrates in this AAA reaction. In addition, the approach exhibited a remarkable superiority in the construction of a stereogenic center involving challenging sterically hindered nucleophiles for both primary and secondary alkyl groups. Extension of this method under continuous flow conditions was also performed with excellent enantioselectivity in a short residence time. Mechanistic experiments indicated that the reaction proceeded through an in situ generated allylic bromide intermediate. All these advantages demonstrated that this chiral catalytic system is a valuable complement for existing asymmetric catalytic methods.