Synthesis Of Novel Chiral Diamine Organocatalysts And The Catalytic Effects On The Stoichiometric Asymmetric Direct Aldol Reaction In The Presence Of Water

In the latest decade, asymmetric organocatalysis has become an important area of research in organic synthesis. Aldol reaction is recognized as one of the most powerful carbon-carbon bond-forming reactions in modern organic synthesis, creating theβ-hydroxy carbonyl structural unit found in many natural products and drugs, has received much attention in recent years.The donors of these aldol reactions are usually used in a large excess amount, which hampers its practical application. Therefore, it is necessary to developmore effective ways to lower the amount of donors. However, unlike enzymatic reactions in nature that occur in water, enantioselective organocatalytic processes have typically been carried out in organic solvents or in mixed aqueous organic solvent, under mild conditions. Therefore, highly efficient catalytic system, which gives high enantioselectivity for a broad range of substrates in water, is still limited and currently a sought-after goal in modern chemistry.In this dissertation, a novel primary-tertiary diamine salt can be easily prepared and be efficient catalyst for direct aldol reaction, by using stoichiometric amounts of cyclic ketones and various aryl aldehydes in the presence of water from green chemistry and atom-economical perspectives, with good yields, diastereoselectivities (up to 99:1), and enantiomeric excesses (up to 98%). This novel catalyst can also be efficiently used in large-scale reactions with the enantioselectivity being maintained at the same level, which offers a great possibility for applications in industry.