Studies in Stereochemistry

分子的化学和物理性质不仅由它们的元素组成决定，而且由它们的形状（立体化学）决定。这些研究将为形状在控制化学性质方面的作用提供进一步的信息。这对于理解分子如何在生物系统中相互作用尤为重要。该项目的具体立体化学研究分为四个方面：(A)构象分析-将研究1,2,3,4- n -甲基四氢喹啉及其盐的构象行为，以及旋光度与顺式-3-羟基硫烷亚砜和其他构象和氢键的关系化合物;(B)核磁共振波谱-核磁共振波谱研究将处理O-17核磁共振，特别是氢键的影响，应用于糖衍生物的机理研究和光谱；(C)不对称合成-不对称合成的研究将涉及先前研究的1,3-恶唑烷系统，也将包括手性1,3-恶唑烷作为立体选择性合成模型的方法学研究。此外，在涉及克拉姆循环规则的此类研究中，螯合作用的重要性的机制研究将通过停止流动方法进行；碳离子化学-碳离子研究将涉及从1,3-草硫烷和1,3-二氧六烷衍生的碳离子，并将包括通过停止流动核磁共振研究其转化速率的努力。

The chemical and physical properties of molecules are determined not only by their elemental composition, but also by their shape (stereochemistry). These studies will provide further information on the role of shape in controlling chemical properties. This is particularly important in understanding how molecules interact in biological systems. The specific stereochemical studies of this project are in four areas: (A) Conformational Analysis - The conformational behavior of 1,2,3,4-N-methyltetrahydroquinolines and their salts will be studied as well as the relation of optical rotation to conformation and hydrogen bonding in cis-3-hydroxythiane sulfoxide and other compounds; (B) NMR Spectroscopy - NMR spectroscopic studies will deal with O-17 NMR, especially effects of hydrogen bonding, application to mechanistic studies and spectra of sugar derivatives; (C) Asymmetric Synthesis - The studies in asymmetric synthesis will involve the previously investigated 1,3-oxathiane system and will also encompass methodological studies of chiral 1,3-oxazanes as molds for stereoselective syntheses. Further, mechanistic studies of the importance of chelation in such studies involving Cram's cyclic rule will be undertaken by stop-flow methods; and (D) Carbanion Chemistry - The carbanion studies will involve carbanions derived from 1,3-oxathiane and 1,3-dioxane and will encompass efforts to investigate their rate of inversion by stop-flow nmr.