Copper-Catalyzed Enantioselective [1,3] O-to-C Rearrangement of Heteroaryl Alkyl Ethers.

Herein, we extend a catalytic enantioselective dearomative [1,3] O-to-C rearrangement constructing C2 quaternary benzofuranones/3-oxindoles from readily accessible C3-heteroaryl alkyl ethers. The abundant Cu(II) salts with (S,S)-BOX were used as catalysts. The reaction features a broad scope (over 30 examples) with good yields (up to 99%) and enantioselectivity (up to 99% ee). Control experiments revealed that the [1,3] rearrangement proceeded via zwitterionic intermediates. Additionally, compound 2w was discovered to be selectively enriched in lipid-rich tissues of zebrafish and display blue fluorescence emission, suggesting potential applications as a new chemical.