New Efficient Organocatalyst Supported on Simple Ionic Liquid as Recoverable System for Asymmetric Diels-Alder Reaction in Presence of Water

The synthesis, characterization and evaluation of a new highly efficient organocatalyst, namely (5S)-2,2,3-trimethyl-5- thiobenzylmethyl-4-imidazolidinone hydrochloride has been achieved. The catalyst possesses important structural features that should increase the catalytic efficiency and solubility in polar media. The application of ionic liquid-supported imidazolidinone catalyst in enantioselective Diels–Alder reactions was investigated. The Diels– Alder reactions of several dienes and dienophiles proceeded efficiently in the presence of the catalyst to provide the desired products in a range from moderate to good yields and from good to excellent enantioselectivities. The conformational study confirms that in the transition state the Re face is completely shielded by phenyl ring preferring approach on less hindered Si face. Particularly remarkable is the fact that the entire system IL/HCl 0.01 M/Catalyst can be recovered and reused for up to six runs without appreciable loss of catalytic activity