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.
提供了一种新的有机催化方法,用于将2-氧
吲哚与α,β-不饱和酮进行1,4-加成,采用廉价且易得的l-脯
氨酸和非手性的反式-
2,5-二甲基哌嗪作为催化体系。反应产生的
吲哚衍
生物具有相邻的季碳和三级碳中心,产率高达99%,对映体过量达到91%。