Oxathiaborolium-Catalyzed Enantioselective [4 + 2] Cycloaddition and Its Application in Lewis Acid Coordinated and Chiral Lewis Acid Catalyzed [4 + 2] Cycloaddition
作者:Ramalingam Boobalan、Rong-Jie Chein
DOI:10.1021/acs.orglett.1c02345
日期:2021.9.3
catalysts for [4 + 2] cycloaddition. Oxathiaborolium pentachlorostannate (5–10 mol %) successfully catalyzed cycloaddition of various dienes and dienophiles to afford cycloadducts with excellent enantioselectivity (20 examples, up to 99% ee). This super Lewis acid also exhibited good enantioselectivity for the first Lewis acid coordinated and chiral Lewis acid catalyzed [4 + 2] cycloaddition to α,β-unsaturated