Divergent Stereocontrol of Acid Catalyzed Intramolecular Aldol Reactions of 2,3,7-Triketoesters: Synthesis of Highly Functionalized Cyclopentanones

The intramolecular acid catalyzed aldol cyclization of 2,3,7-triketoesters formed from ζ-keto-α-diazo-β-ketoesters provides highly functionalized cyclopentanones with good diastereoselectivity in high overall yields via kinetically controlled and stereodivergent catalytic processes. Lewis acid catalysis gives high selectivity for the 1,2-anti tetrasubstituted cyclopentanones, whereas Brønsted acid catalysis produces the corresponding 1,2-syn diastereomer.

由ζ-酮-α-重氮-β-酮酸酯（ζ-keto-α-diazo-β-ketoesters）制备得到的2,3,7-三酮酸酯，经分子内酸催化羟醛环化反应，可通过动力学控制且立体发散的催化过程，以优异总收率与良好非对映选择性得到高官能团化环戊酮类化合物。其中，路易斯酸（Lewis acid）催化对1,2-反式四取代环戊酮展现出优异的选择性，而布朗斯特酸（Brønsted acid）催化则可生成对应的1,2-顺式非对映异构体。