L-proline-catalyzed asymmetric michael addition of 2-oxindoles to enones: A convenient access to oxindoles with a quaternary stereocenter

Article abstract of DOI:10.1055/s-0030-1259527

A new organocatalytic approach for 1,4-conjugate addition of 2-oxindoles to α,β-unsaturated ketones using the combination of readily available and nonexpensive l-proline and achiral trans-2,5-dimethylpiperazine as catalytic system is provided. The reaction results in oxindole derivatives with vicinal quaternary and tertiary carbon centers in up to 99% yield and 91% ee. Georg Thieme Verlag Stuttgart.