Asymmetric Organocatalytic Direct Aldol Reactions of Ketones with α-Keto Acids and Their Application to the Synthesis of 2-Hydroxy-γ-butyrolactones
作者:Xiao-Ying Xu、Zhuo Tang、Yan-Zhao Wang、Shi-Wei Luo、Lin-Feng Cun、Liu-Zhu Gong
DOI:10.1021/jo701868t
日期:2007.12.1
of organocatalysts for the asymmetric direct aldol reactions of ketones with α-keto acids were designed on the basis of molecular recognition and prepared from proline and aminopyridines. The organic molecule 8e, derived from proline and 6-methyl-2-amino pyridine, was the best catalyst, affording excellent enantioselectivities (up to 98% ee) for the direct aldol reactions of acetone or 2-butanone with
在分子识别的基础上,设计了多种有机催化剂,用于酮与α-酮酸的不对称直接羟醛直接反应,并由脯氨酸和氨基吡啶制备。有机分子8e衍生自脯氨酸和6-甲基-2-氨基吡啶的最佳催化剂,对丙酮或2-丁酮与各种α-酮酸和用于各种无环脂族酮与3-(2-硝基苯基)-2-氧代丙酸的反应。通过非对映选择性还原和内酯化的反应序列可以将羟醛加成物转化为2-羟基-γ-丁内酯。对过渡态的实验和理论研究表明,有机催化剂的酰胺N和吡啶N分别与α-酮酸的酮氧基和羧酸羟基选择性地形成氢键。这两个氢键相互作用对于直接不对称羟醛缩合的反应性和对映选择性很重要。