In the context of asymmetric synthesis, the use of organocatalysts has great advantages over transition metal catalysts in terms of ease use and more importantly, compatibility with the environment. 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 and 1,3-dicarbonyl compounds as donors. However, there are very few studies using thiol derivatives as nucleophiles, even fewer organocatalytic works. In this study, methyl thioglycolate is used for carrying out asymmetric sulfa-Michael additions to chalcone type acceptors (Scheme 1), in the presence of DMAP or squaramide based bifunctional organocatalysts developed in our research group. During the work, eleven of the aforementioned catalysts were scanned to find the best working catalyst for the chosen reaction. Then the reaction conditions were optimized in terms of catalyst loading, temperature control, solvent screening, addition time and concentration. After that, derivatization studies were done under the optimized condition, which yielded a number of substituted sulfa-Michael adducts with 67 - 99% <i>ee.</i>

Asymmetric organocatalytic Michael additions of methyl thioglycolate to various acceptors

253rd National Meeting (2017)

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