Michael reaction with recovery of the catalyst

A process of carrying out a Michael reaction with recovery of the catalyst, the process comprising:

• providing a first compound of the general formula (1):
• wherein ar1 and ar2 are independently from one another an aromatic moiety with 5 to 30 carbon atoms and 0 to 5 heteroatoms selected from the group consisting of N, O, S, Se and Si, and
• providing a second compound of the general formula (2):
• wherein R1 is one of an aliphatic, an alicyclic, an aromatic and an arylaliphatic group with 3 to 30 carbon atoms and 0 to 5 heteroatoms selected from the group consisting of N, O, S, Se and Si, and
• R2 is one of CN, CO—R5, COOH, CHO, NO2, and SO2—R5, wherein R5 is one of an aliphatic, an alicyclic, an aromatic and an arylaliphatic group with 1 to 30 carbon atoms and 0 to 5 heteroatoms selected from the group consisting of N, O, S, Se and Si;
• providing a catalyst of the general formula (4):
• wherein R3 is one of H, OMe, OH, OTf, SH, and NH2;
• R4 is one of OH and N(R8)H;
• wherein R8 is one of H, a carbamoyl group, and a thiocarbamoyl group, and
• represents one of a single and a double bond;
• contacting in an aliphatic ether solvent the first compound of formula (1), the second compound of formula (2) and the catalyst of formula (4), thereby forming a reaction mixture,
• allowing the first and the second compound to undergo a Michael reaction, thereby allowing the formation of an adduct between the first compound and the catalyst of the general formula (4);
• and
• collecting the adduct between the first compound and the catalyst of the general formula (4), wherein the adduct is precipitated and collected.