Studies On Asymmetric Synthesis Of Imidazo [1,2-α] Tetrahydropyridine Catalyzed By Br(?)nsted Acid And Asymmetric Addition Of Methyl Propiolate To Aldehydes

This thesis is composed of three parts:(1) Asymmetric multicomponent reactions (AMCRs), which lead to the formation of one or more chiral center catalyzed by chiral Br(?)nsted acids, are very efficient synthetic methods and they are widely used in the synthesis of nature products. Recent achievements are introducing in AMCRs using 1,1'-bi-2-naphtohol (BINOL)-derived phosphoric acids as chiral Bronsted acid catalysts in this chapter.(2) We have studied three-component reaction of acetophenone, chalcone and 1,2-ethylenediamine catalyzed by chiral phosphoric acids and make a little headway. The optimization of the reaction conditions is underway.(3) Three chiralβ-hydroxy amide ligands were prepared by the reaction of benzyl chloride with amino alcohols derived from (S)-tyrosine. The titanium(IV) complex of chiral ligand was found to be an effective catalyst for the asymmetric addition of methyl propiolate to aliphatic and aromatic aldehydes under mild conditions. Theγ-hydroxy-α,β-acetylenic esters were obtained in excellent enantiomeric excesses (up to 94% ee) under optimized conditions.