Organocatalytic Aldol Condensation of Thiazolidinedione Derivatives

Chauhan, Ajay (2011) Organocatalytic Aldol Condensation of Thiazolidinedione Derivatives. Masters thesis, Indian Institute of Science Education and Research, Kolkata.

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Abstract

Recent years have witnessed an explosive growth in the field of organocatalysis, especially in asymmetric enamine and iminium catalysis. The use of simple amino acids as catalyst for the intermolecular direct aldol reaction at the beginning of this century became a true milestone in the growth of organocatalysis as a useful synthetic strategy. Since then, a plethora of new organocatalytic systems have been developed allowing to reach extraordinary levels of efficiencies, widening the scope of substrates used. Several modifications have been introduced to overcome some of the initial drawbacks, such as long reaction times, high catalyst loading, excess of reagents, etc., improving the expectations for their use in large scale synthesis. The acquired knowledge in this area has allowed the application of this strategy to be used in the synthesis of natural products. Thiazolidinedione units are important structural subunits present in many natural products and biologically active compounds. In this thesis we describe aldol condensation of N-substituted-2,4-thiazolidinedione derivatives 1 with a variety of aromatic aldehydes 2 using different amino acid catlysts 3. We have investigated the effects of solvent and different amino acids on the reaction to achieve the corresponding thiazolidine containing b-hydroxy carbonyl products 4 and 5 in high yield and diasterioselectivity. Amino acids catalysts 3 efficiently catalyzed aldol reaction between thiazolidinediones 1 and a variety of aromatic aldehydes 2 to give the corresponding syn and anti hydroxy thiazolidinediones 4 and 5 in good to excellent yields and moderate distreoselectivity.

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