Asymmetric Synthesis of Chromans Through Bifunctional Enamine-Metal Lewis Acid Catalysis.

Jacqkis Davis, Mojgan Gharaee, Chamini V Karunaratne, Jose Cortes Vazquez, Mikayla Haynes, Weiwei Luo, Vladimir N Nesterov, Thomas Cundari, Hong Wang

Chemistry (Weinheim an der Bergstrasse, Germany) 2022 May 11

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Cooperative enamine-metal Lewis acid catalysis has emerged as a powerful tool to construct carbon-carbon and carbon-heteroatom bond forming reactions. A concise synthetic method for asymmetric synthesis of chromans from cyclohexanones and salicylaldehydes has been developed to afford tricyclic chromans containing three consecutive stereogenic centers in good yields (up to 87 %) and stereoselectivity (up to 99 % ee and 11 : 1 : 1 dr). This difficult organic transformation was achieved through bifunctional enamine-metal Lewis acid catalysis. It is believed that the strong activation of the salicylaldehydes through chelating to the metal Lewis acid and the bifunctional nature of the catalyst accounts for the high yields and enantioselectivity of the reaction. The absolute configurations of the chroman products were established through X-ray crystallography. DFT calculations were conducted to understand the mechanism and stereoselectivity of this reaction. © 2022 Wiley-VCH GmbH.

Citation

Jacqkis Davis, Mojgan Gharaee, Chamini V Karunaratne, Jose Cortes Vazquez, Mikayla Haynes, Weiwei Luo, Vladimir N Nesterov, Thomas Cundari, Hong Wang. Asymmetric Synthesis of Chromans Through Bifunctional Enamine-Metal Lewis Acid Catalysis. Chemistry (Weinheim an der Bergstrasse, Germany). 2022 May 11;28(27):e202200224