l-Proline-Catalyzed Asymmetric Michael Addition of 2-Oxindoles to Enones: A Convenient Access to Oxindoles with a Quaternary Stereocenter
作者:Svetlana Tsogoeva、Matthias Freund
DOI:10.1055/s-0030-1259527
日期:2011.3
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%。