Reactivity of the Carbocations Stabilized by Divalent Sulfur and Application to Organic Synthesis

二价硫稳定碳正离子的反应活性及其在有机合成中的应用

• 批准号: 60470094
• 负责人: OKUYAMA Tadashi
• 金额: $ 0.38万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1985
• 资助国家: 日本
• 起止时间: 1985 至 1986
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-60470094/
• 关键词: Carbocation; Ketene dithioacetal; Ortho ester; Photochemical ionization; Flash photolysis; 閃光光分解; 加水分解; 二価硫黄

A new simple method for isolation of sulfur-stabilized carbocations, 1,3-dithiolan-2-ylium and 1,3-dithian-2-ylium ions, as salts was presented, and the isolated salts were converted to ketene dithioacetals and ortho esters. Reactions of the salts with nucleophiles, such as thiols and sulfinates afforded adducts, which were used as precursors for photochemical generation of dithio carbocations.Reactions of the isolated salts in aqueous solution were kinetically examined and a detailed mechanism of the breakdown of the tetrahedral intermediate was presented. Hydrolysis of Mixed O,S-ortho esters also provided useful information on the mechanism of the breakdown of the tetrahedral intermediate.Kinetic investigations on the acid-catalyzed hydrolysis of ketene dithioacetals showed that the dithio carbocation intermediates easily deprotonate; i. e., the protonation is reversible. Effects of an internal hydroxyl group on the hydrolysis of ketene dithioacetal resulted in a discovery of a new mode of anchimeric assistance; an internal solvation mechanism.Flash photolysis was carried out with a xenone lamp on aqueous solutions of 2-(p-toluene-sulfonyl)-1, 3-dithiolane and 2-(p-chlorophenylthio)-1,3-dithiolane, and their 2-phenyl derivatives. UV spectra, rapidly scanned with an MCPD detector, showed that the transient intermediate is dithiolanylium ion. Decay curves of the transient cation were more rapid than those expected for the first-order decay and recombination of the cation and the counter anions formed was considered to contribute to this reaction. In the presence of thiol or sulfinate, the decay of the cation followed the first-order kinetics and the second-order rate constants for the reactions with the nucleophiles were obtained.Further determinations of rate constants for reactions of a variety of nucleophiles and carbocations are planned.

出现盐时，一种新的简单方法，用于分离硫稳定的碳钙化，1,3-二硫代二醇-2-基群和1,3-二硫代-2-基离子，并将分离的盐转化为酮二硫代乙烯酯和矫正器。盐与亲核试剂的反应，例如硫醇和硫酸盐，加合物，它们用作光化学生成Dithio碳的前体。在水溶液中分离的盐的反应是在水溶液中进行的，并具有详细的介绍性溶液中的分解机制。混合O的水解，S-otho酯还提供了有关四面体中间体分解机制的有用信息。对酸催化的酮二硫代乙酸酯水解的运动研究表明，Dithio Carbocation IntermedimedMedimedInderes易于去质子甲酸酯。我。例如，质子化是可逆的。内部羟基对酮二乙烯水解水解的影响导致发现了一种新的锚固辅助模式。在2-（p-二苯甲 - 磺酰基）-1，3-二硫代烷和2-（p-氯苯基thio）-1,1,3-二硫代硫代和2-苯基衍生物的水溶液上，用异酮灯在水溶液上使用异酮灯进行了内部溶剂化机制。用MCPD检测器迅速扫描的紫外光谱表明瞬态中间体是二硫醇离子。瞬态阳离子的衰减曲线比阳离子的一阶衰变和重组的预期速度更快，并且形成的反阴离子被认为有助于这种反应。在存在硫醇或硫酸盐的情况下，阳离子的衰变遵循了一阶动力学，并计划了速率常数的多种核噬菌体和碳酸化的反应的速率常数。

项目成果

Tadashi Okuyama: "Mechanism of Hydrolysis of 1,3-Dithiane Derivatives. Breakdown of the Tetrahedral Intermediate" J. Org. Chem.51. 4988-4990 (1986)

Tadashi Okuyama：“1,3-二噻烷衍生物的水解机制。四面体中间体的分解”J. Org。

奥山格: Can.J.Chem.64. 1116-1123 (1986)

奥山治：Can.J.Chem.64。1116-1123（1986）

奥山格: Bull.Chem.Soc.Japan. 59. 327-328 (1986)

Itaru Okuyama：Bull.Chem.Soc.Japan 59. 327-328 (1986)。

奥山格: J.Am.Chem.Soc.107. 4224-4229 (1985)

奥山治：《J.Am.Chem.Soc.107》4224-4229（1985）

奥山格: Bull.Chem.Soc.Japan. 59. 453-456 (1986)

Itaru Okuyama：Bull.Chem.Soc.Japan 59. 453-456 (1986)。