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.
Organocatalytic Enantioselective Conjugate Additions to Enones
作者:Jian Wang、Hao Li、Liansuo Zu、Wei Jiang、Hexin Xie、Wenhu Duan、Wei Wang
DOI:10.1021/ja065187u
日期:2006.10.1
Conjugateaddition reactions of a wide range of nucleophilic enol species with enones, catalyzed by a cinchona alkaloid derived thiourea organocatalyst, have been developed with attending good yields and high enantioselectivities under a mild reaction condition. The general method provides an efficient approach to the preparation of versatile building blocks possessing various functional groups.