PEG-Solvent System for L-proline Catalyzed Wieland - Miescher Ketone Synthesis
The Wieland-Miescher ketone 4 serves as starting material for a wide range of natural product synthesis.This
procedure represents one of the most efficient method for the synthesis of Wieland - Miescher ketone 4 with 1 mol% catalyst
loading. PEG (400) mediated proline was used as catalyst to achieve the Wieland - Miescher ketone 4 via a nonselective
conjugated addition reaction tailed by an enantioselective intermolecular Aldol condensation reaction of triketone
3 intermediate. All the reaction products were well characterized by sophisticated analytical techniques such as
NMR, FTIR, HPLC, HRMS etc. Short reaction time, 8 times recycling of the catalyst, good yield (90%) and selectivity
(99% ee) are the major outcomes of this proposed protocol.
Keywords: Amino acid, asymmetric synthesis, biologically active molecules, catalyst recycling, immobilized catalysis, ionic
liquid, L-proline, PEG (400), organocatalysis, polymeric immobilization, wieland-miescher ketone.
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