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.

合成光学纯硼配合物，氨基酸的方法， 提出了酰胺和酯。 该方法的关键新功能 取决于通过手性“ Ate”复合物控制硼立体化学的控制 晶格效应。 从硼获得的环状“ Ate”配合物 试剂和手性韧性底物作为混合物形成 非对映异构体，但结晶允许完全转换为一个 结晶异构体。 随后的化学转化将进行 通过可逆的“ Ate”以下以下以下的非对映异构体互连的温度 复杂的解离，并将利用“不对称记忆” 暂时立体硼。 这个概念的应用 描述了天然和不自然氨基酸的合成，包括 催化烯烃烷基化的方法。 提出了一种使用新方法来对映射控制的烯酸酯化质子化 路易斯酸诱导的内部质子回归。 最后，上述某些方法将在特定的简短路线中使用 手性抗叶剂和不寻常的手性硼催化剂。