ASYMMETRIC MEMORY AT HETEROATOMS

异原子的不对称存储器

• 批准号: 2182706
• 负责人: EDWIN VEDEJS
• 金额: $ 13.94万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-08-01 至 1995-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2182706
• 关键词: alkylation; amides; aminoacid; aminoacid analog; boron; catalyst; chemical synthesis; crystallization; cyclic compound; enolate; esters; metal complex; protonation; saturated /unsaturated bonds; stereochemistry; stereoisomer; temperature

Methods for synthesis of optically pure boron complexes, amino acids, amides, and esters are proposed. The critical new feature of the method depends on control of boron stereochemistry in a chiral "ate" complex by crystal lattice effects. The cyclic "ate" complex obtained from the boron reagent and a chiral difunctional substrate is formed as a mixture of diastereomers, but crystallization allows complete conversion into one crystalline isomer. Subsequent chemical transformations would be performed below the temperature for diastereomer interconversion via reversible "ate" complex dissociation, and would take advantage of the "asymmetric memory" of temporarily stereogenic boron. Applications of this concept to the synthesis of natural and unnatural amino acids are described, including methods for catalytic enolate alkylation. A new method for enantiocontrolled enolate protonation is proposed using Lewis acid induced internal proton return. Finally, some of the above methods will be used in short routes to specific chiral atropisomers and unusual chiral boron catalysts.

光学纯硼络合物、氨基酸 酰胺和酯。 该方法的关键新特征 取决于手性“ate”络合物中硼立体化学的控制， 晶格效应 从硼化合物中获得的环状“ate”络合物 试剂和手性双官能底物的混合物形成为 非对映异构体，但结晶允许完全转化为一种 结晶异构体 随后的化学转化将进行 低于非对映体通过可逆“ATE”相互转化的温度 复杂的解离，并将利用“不对称记忆” 暂时性的立体硼 将这一概念应用于 描述了天然和非天然氨基酸的合成，包括 催化烯醇化物烷基化的方法。 提出了一种新的对映体控制的烯醇化物质子化方法， 刘易斯酸诱导内部质子返回。 最后，上述方法中的一些将用于短路线，以特定的 手性阻转异构体和不寻常的手性硼催化剂。