Bhanushali Mayur, Zhao Cong-Gui
Department of Chemistry, University of Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249, USA.
Tetrahedron Lett. 2012 Jan 18;52(3):359-362. doi: 10.1016/j.tetlet.2011.11.056. Epub 2011 Nov 19.
The enantioselective cross aldol reaction of 1-benzyl 4,5-dioxo-2-aryl-4,5-dihydro-1H-pyrrole-3-carboxylates and ketones was studied with proline derivatives or cinchona alkaloid-derived primary amines as the catalysts for the first time. trans-4-Benzoyloxy-L-proline (15) was found to be the best catalyst for acyclic ketones. For cyclohexanone, the best results were achieved with 9-deoxy-9-epi-aminoquinine (18) as the catalyst in the presence of racemic 1,1'-binaphthyl-2,2'-diyl hydrogen phosphate (19) as the cocatalyst. Using these protocols, 3-alkyl-3-hydroxy-1H-pyrrol-2(3H)-one derivatives were obtained in excellent yields and good to high ee values (up to 94% ee).
首次以脯氨酸衍生物或金鸡纳生物碱衍生的伯胺为催化剂，研究了1-苄基-4,5-二氧代-2-芳基-4,5-二氢-1H-吡咯-3-羧酸酯与酮的对映选择性交叉羟醛反应。发现反式-4-苯甲酰氧基-L-脯氨酸（15）是用于无环酮的最佳催化剂。对于环己酮，在消旋的1,1'-联萘-2,2'-二基磷酸氢酯（19）作为助催化剂存在下，以9-脱氧-9-表氨基奎宁（18）为催化剂可获得最佳结果。使用这些方法，以优异的产率和良好至高的对映体过量值（高达94% ee）获得了3-烷基-3-羟基-1H-吡咯-2(3H)-酮衍生物。
