Scientists of the ZIOC developed organocatalytic eco-friendly method for the synthesis of chiral chromones and flavonoids

Asymmetric organocatalysis is a young and dynamically developing area of modern organic chemistry. The importance of this field of science was recognized by the Nobel Prize in Chemistry in 2021 to B. List and D. McMillan — the authors of key studies on this topic. One of the most important processes of organocatalytic synthesis, namely the formation of a carbon-carbon bond, is the Michael reaction, which is successfully catalyzed by bifunctional tertiary aminosquaramides. Due to the selective hydrogen bonding of the reagents with the catalyst, it is possible to provide such an approach of the nucleophile to the electrophile so that a high level of stereoinduction is achieved.

Researchers of the I.N. Nazarov Laboratory of Fine Organic Synthesis of the Zelinsky Institute proposed an efficient and environmentally friendly method for the synthesis of bioactive chromones and their derivatives through olefination with electron-deficient alkenes (including those of the organometallic series) using a chiral C2-symmetric organocatalyst based on square acid. All compounds were obtained in high yields (80-99%) and enantioselectivity up to 99% ee. Reactions are easily scalable to gram quantities. It has also been shown that the organocatalyst can be regenerated and reused in at least 10 reaction cycles without significant loss of efficiency.

Source:
Ruslan A. Kovalevsky, Alexander S. Kucherenko, Alexander A. Korlyukov, Sergei G. Zlotin Asymmetric Conjugate Addition of 3-Hydroxychromen-4-ones to Electron-Deficient Olefins Catalyzed by Recyclable C2-Symmetric Squaramide Adv. Synth. Catal. 2021, accepted manuscript. DOI: 10.1002/adsc.202101019.