Synthesis of novel phase transfer catalysts derived from proline-mandelic acid/tartaric acid: their evaluation in enantioselective epoxidation and Darzen condensation

Abstract : Herein, we have described the synthesis of novel chiral cyclic phase transfer catalysts (PTCs). These catalysts are synthesized from proline, mandelic acid and tartaric acid by using simple synthetic methods with competitive yields. These chiral cyclic phase transfer catalysts have been characterized by ¹ H NMR and ¹³ C NMR spectroscopy, IR spectroscopy and elemental analysis. The effectiveness of these novel chiral cyclic phase transfer catalysts was evaluated by applying them in the enantioselective epoxide synthesis from α , β unsaturated ketone (chalcone) and Darzens condensation. The obtained results show that the synthesized derivatives of proline, mandelic acid and tartaric acid are effectual as PTCs. Graphical Abstract: SYNOPSIS This paper shares the synthesis and characterization of novel chiral phase transfer catalysts from proline, mandelic acid and tartaric acid. The synthesis of these newly explored cyclic derivatives is reported by using a simple method with competitive yields. The effectiveness of these novel chiral cyclic phase transfer catalysts was evaluated by applying them in enantioselective epoxide synthesis from α, β unsaturated chalcone and in Darzen condensation. The obtained results show that the synthesized derivatives of proline, mandelic acid and tartaric acid are effectual as PTCs and useful towards the synthesis of enantioselective epoxide. [Figure not available: see fulltext.].