A strategy for the chemodivergent application of thiocyanate-containing protic ionic liquids was proposed with the participation of the Zelinsky Institute

One of the important directions in the development of synthetic organic chemistry is the creation of chemodivergent synthesis methods, according to which the same (or structurally similar) starting compounds can be converted into various products with a slight variation in the process conditions. In this regard, protic ionic liquids (PILs, salts of organic bases and Brönsted acids with a melting point below 100 °C) are quite attractive, the “fine-tuning” of their properties allows you to control the direction of the reaction.

With the participation of the researchers of the Laboratory of Directional Functionalization of Organic Molecular Systems of the Zelinsky Institute the study of thiocyanate-containing protic ionic liquids as triple-purpose reagents that act as regenerated reaction media, acid process initiators, and nucleophile sources, continues. This concept has been applied to chemodivergent opening of 1,3-indanedione-substituted donor–acceptor cyclopropanes. It should be noted that a simple variation of the main component of PIL made it possible to control the selectivity of the process in the framework of the domino transformation and synthesize previously unknown thieno[2,3-c][2]benzazepine and/or unusual spiro[2-thioxopyrrolidine-3,2′-indan-1′,3′-dione] heterocyclic systems. Both products were obtained in 1-methylimidazolium thiocyanate in a ratio depending on the nature of the donor substituent in the starting cyclopropane. In contrast, heating in triethylammonium thiocyanate yielded only pyrrolidine-2-thiones.
 

Source:

Nina K. Ratmanova, Ivan A. Andreev, Vitaly A. Shcherbinin, Olga A. Ivanova, Irina I. Levina, Victor N. Khrustalev, Igor V. Trushkov. Triple role of thiocyanate-containing protic ionic liquids in chemodivergent ring-opening of 1,3-indanedione-derived donor–acceptor cyclopropanes // J. Mol. Liq. 2023, 122401. DOI: 10.1016/j.molliq.2023.122401.