An enantioselective synthesis of biologically important imidazolidines has been achieved via a tandem [3 + 2] cycloaddition/1,4-addition reaction of azomethine ylide and aza-o-quinone methides. With the use of this tool, various imidazolidinederivatives are obtained in good yields with excellent diastereoselectivities and enantioselectivities.
Cu(I)-Catalyzed Highly Enantioselective [3 + 3] Cycloaddition between Two Different 1,3-Dipoles, Phthalazinium Dicyanomethanides and Iminoester-Derived Azomethine Ylides
The Cu(I)-catalyzed highly enantioselective [3 + 3] cycloadditionbetween two different 1,3-dipoles, phthalazinium dicyanomethanides and iminoester-derived azomethine ylides, has been achieved under mild reaction conditions, providing novel chiral heterocyclic compounds, 2,3,4,11b-tetrahydro-1H-pyrazino[2,1-a]phthalazine derivatives, in high yields with excellent diastereo- and enantioselectivies (up
在温和的反应条件下,已实现了Cu(I)催化的两个不同的1,3-偶极,酞菁双氰胺和亚氨基酯衍生的偶氮甲碱的高对映选择性[3 + 3]环加成反应,提供了新颖的手性杂环化合物2,3 ,4,11b-四氢-1 H-吡嗪并[ 2,1- a ]酞嗪衍生物,高收率,具有出色的非对映和对映选择性(高达99%收率,99%ee,> 20:1 dr)。
Enantioselective Copper-Catalyzed [3+3] Cycloaddition of Azomethine Ylides with Azomethine Imines
The more dipoles, the merrier: An asymmetric [3+3] cycloaddition of azomethineylides derived from imines 1 with azomethineimines 2 in the presence of a chiral ferrocenylphosphine–copper catalyst afforded highly functionalized heterocyclic products 3 in high yield with excellent enantio‐ and diastereoselectivity (see scheme; DBU=1,8‐diazabicyclo[5.4.0]undec‐7‐ene). The 1,3‐dipolar reaction partners
Aminocitrate (and homolog) derivatives have been prepared by bis-alkylation of glycinate Schiff bases with bromoacetates (and ethyl acrylate), followed by N-acylation and esters (partial or complete) deprotection. Aminoisocitrate was similarly obtained by mono-alkylation with diethyl fumarate. Evaluation against representative β-lactamases revealed that the free acid derivatives are modest inhibitors
The title compound 4 has been prepared in four steps from ethylglycinate in 63% overall yield. This amino analog of citric acid has been co-crystallized with the class A beta-lactamase BS3 of Bacillus licheniformis and the structure of the complex fully analyzed by X-ray diffraction. Tris-ethyl aminocitrate 3 and the free tris-acid 4 have been tested against a member beta-lactamase from all distinct