Formation of 2H- and 4H-chromene Rings in Intramolecular Rauhut-Currier Reaction, Catalyzed by Lithium Selenolates

In this paper, we present the first example of using a catalytic amount of a nucleophilic seleno-organic catalyst in a tandem seleno-Michael/Michael reaction, leading to the formation of 2H/4H-chromenes. Chromenes represent a highly significant group of oxygen-containing heterocycles commonly found as structural scaffolds in a diverse range of fields such as medicinal chemistry, pharmaceutical agents, drug candidates, synthetic chemistry, and materials chemistry. Various preparation methods have been developed, utilizing different substrates in conjunction with metal catalysts, organocatalysts, Brønsted acids, bases, or Lewis acids. The synthetic utility of lithium selenolates has been demonstrated as efficient nucleophilic catalysts in the Rauhut-Currier cyclization of chalcone derivatives. This methodology allows for the synthesis of 2H- and 4H-chromenes depending on the substituents directly connected to the carbonyl group. The investigation focuses on the impact of various substituents in the aromatic fragment as well as conditions and selenolates. The scope of different starting materials was also considered.