Bifunctional 2-aminodmap/thiourea catalyzed enantioselective michael addition of thioacetic acid to trans-beta-nitrostyrenes

Kabasakal, Zehra
Michael addition reactions as an efficient method for carbon-carbon bond formations have been intensively explored in the context of enantioselective organocatalysis using aldehydes, ketones, 1,3- dicarbonyl compounds and nitroalkenes as donors. However, there are very few studies using thiol derivative as a nucleophile. In this thesis, enantioselective Michael addition reaction of thioacetic acid as Michael donor and 10 trans-β-nitrostyrene derivatives as Michael acceptors have been studied. The products of this reaction are very important candidates for the synthesis of chiral 1,2-aminothiols. Bifunctional acid/base type organocatalyst named as 2-aminoDMAP/thiourea was found as the best organocatalyst. In the first part of the study, optimization studies were done by screening different parameters such as temperature, solvent and catalyst loading. By applying the optimized reaction conditions, thioacetic acid underwent Michael addition reactions with 10 trans-β-nitrostyrene derivatives to afford enantiomerically enriched thioester type addition products up to 96% ee.