Ionic Liquid Mediated MacMillan Imidazolidinone Organocatalyst for Diels Alder Reaction

Abstract

Background: The Diels-Alder reaction is one of the important and highly applicable reactions in the area of organic synthesis. It is useful to obtain six membered cyclic compounds using onestep inter- or intra-molecular reaction protocol. The high degree of regio- as well as stereoselectivity can be easily obtained by this reaction. The aim of this proposed work is to increase the efficiency of MacMillan catalyst using ionic liquid medium to obtain the Diels-Alder reaction product in good yield and selectivity. Methods: MacMillan’s catalyst was used in pyridinium based ionic liquids to promote Diels-Alder reaction. After completion the reaction product was isolated by simple ether washing and the catalytic system was reused for the next reaction cycle. Results: A highly enantio- and diastereoselective Diels–Alder reaction was obtained by using MacMillan’s catalyst in ionic liquid medium. Surprisingly, Ionic liquid mediated MacMillan’s catalyst was found highly active in term of yield and selectivity for the Diels -Alder reaction with the added advantage of 8 times catalyst recycling. Synthesis of steroid, is the major outcome of our developed protocol. Conclution: MwacMillan’s catalyst was found highly active in terms of yield and selectivity. We also extended the application of our proposed protocol and successfully synthesized the biologically active steroid. Keywords: Diels- alder reaction, ionic liquid, MacMillan’s catalyst, steroid synthesis.