Diaminomethylenemalononitrile organocatalyst 1 efficiently promotes the asymmetric conjugateaddition of malonates to α,β-unsaturated ketones to afford the corresponding addition products in high to excellent yields with up to 98% ee.
Chiralbisphosphazides complexed with lithium salts efficiently catalyze the direct enantioselective 1,4-addition of dialkyl malonates to acyclic enones. Spectroscopic studies on the stoichiometry of the bisphosphazide and lithium salt have indicated the formation of a 1:1 species as the active enantioselectivecatalyst. It is suggested that the catalyst generates a complex of the protonated phosphazide
Lithium Binaphtholate-Catalyzed Michael Reaction of Malonates with Maleates and Its Application to the Enantioselective Synthesis of Tricarboxylic Acid Derivatives
The Michael reaction of malonates with maleates afforded the corresponding adducts in high yields with high enantioselectivities (up to 98% enantiomeric excess (ee)) by using dilithium 3,3'-dichlorobinaphtholate as a catalyst. The obtained Michael adducts could be converted to optically active tricarboxylic acid (TCA) derivatives via the Krapcho reaction.
A highlyenantioselectiveMichaeladdition of malonate derivatives to chalcone derivatives catalyzed by an N,N′‐dioxide–ScIII complex was developed, which tolerated a broad range of substrates in moderate to excellent yield with 96–99 % ee. The reaction proceeded well in EtOH or water and could be scaled to grams in good yield with 98 % ee using only 1 mol % ligand L–scandium(III) complex as a catalyst