Isatin-derived ketimines undergo enantioselective alkynylation reactions in the presence of copper iodide and easily accessible guanidine-amides. The corresponding 3-alkynyl-3-aminooxyindoles are obtained in up to 95% yield and 96% ee. The guanidine plays a role in the formation of copper acetylide and the enantiodetermining step and the basic additive is excluded.
3-Amino-benzofuran-2,5-diones containing a chiral amino acid residue were achieved through BG-1·HBPh4 catalyzed enantioselective Michael addition/lactonization cascade reaction of p-quinols with azlactones.
A new asymmetric preparative method of 3-aminodihydrocoumarins via reactions of azlactones and 2-nitrovinylphenols using chiral bifunctional guanidine catalysts.
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