Stereoselective Cyclization using Pd(II)-catalyst via Hemiacetal Intermediates and its Application to Sugar Synthesis

Pd(II) 催化剂通过半缩醛中间体的立体选择性环化及其在糖合成中的应用

• 批准号: 13640527
• 负责人: MIYAZAWA Masahiro
• 金额: $ 2.18万
• 依托单位: Toyama University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13640527/
• 关键词: Palladium catalysy; Hemiacetal; Heterocyclization reaction; Glycosidation; Origo saccharides; Stereoselective; Ribose; DNA; 糖; スピロケタール

We recently reported the intramolecular substitution of an allyl alcohol by a heteroatom using a palladium (II) catalyst without activation of the allylic alcohol. We report here highly stereoselective intramolecular cyclization of 6- and 7-formyl allylic alcohols using palladium (II) catalyst in the presence of alcohol via unstable hemiacetal intermediates, in which cyclization occurs without activation of the allylic alcohol in this case too.1. Stereoselective Cyclization using Pd (II)-catalyst via Hemiacetal IntermediatesTreatment of 7-hydroxy-3-phenyl-5-hexenal with 5 mol% bis(benzonitrile)palladium (II) chloride in THF in the presence of primary, secondary, and tertiary alcohol afforded 6-membered cyclic acetals in 50〜80% yield with highly stereoselectivity. Especially, the relative stereochemistry at C4 and C6 position was 100% cis-selective by treatment with secondary and tertiary alcohols.2. Total synthesis of D-riboseA total synthesis of the furanose form of D-ribose, which is … More component of RNA, is described. The optically active cyclized precursor was prepared from (Z)-2-butene-I,4-diol using asymmetric esterification in 13 steps. Treatment of the precursor with Pd (II) catalyst gave the cyclized product Finally, D-ribose was prepared from the cyclized product in 2 steps.3. Total synthesis of 2-deoxy-D-riboseA total synthesis of the furanose form of 2-deoxy-D-ribose, which is component of DNA, is described. Preparation of the cyciized precursor required 8 steps and proceeded in 53% overall yield from (S)-malic acid. Treatment of the precursor with Pd (II) catalyst gave the cyclized product with good stereoselectivity. 2-Deoxy-D-ribose was prepared from the cyclized product in 5 steps.4. Synthetic studies of Origo saccharidesA disaccharide was obtained under mild conditions through palladium (II) catalyzed coupling reaction of the cyclized precursor and 2-deoxy-D-ribose derivative. The present method should provide a powerful tool in organic synthesis including carbohydrate synthesis. Less

我们最近报道了用钯（II）催化剂在不激活烯丙醇的情况下，用杂原子取代烯丙醇的分子内反应。我们在此报道了6-和7-甲酰基烯丙醇在不稳定的半缩醛中间体存在下，通过钯（II）催化剂在分子内进行了高度立体选择性的环化，在这种情况下，烯丙醇也没有被激活。在四氢呋喃中，在伯、仲、叔醇的存在下，用5摩尔二（苯腈）氯化钯（II）对7-羟基-3-苯基-5-己烯醛进行立体选择性环化反应，得到了收率为50 ~ 80%的6元环缩醛，具有高度的立体选择性。特别是在C4和C6位置的相对立体化学中，仲、叔醇的选择性为100%顺式。d -核糖的总合成描述了呋喃糖形式的d -核糖的总合成，它是RNA的主要组成部分。以(Z)-2-丁烯- 1,4 -二醇为原料，经13步不对称酯化反应制备了具有光学活性的环化前驱体。前驱体经Pd （II）催化剂处理得到环化产物，经2步合成d -核糖。2-脱氧d -核糖的总合成描述了2-脱氧d -核糖的呋喃糖形式的总合成，它是DNA的组成部分。环化前体的制备需要8个步骤，从(S)-苹果酸中获得53%的总收率。前驱体经Pd （II）催化剂处理后，产物具有良好的立体选择性。由环化产物经5步合成2-脱氧- d -核糖。通过钯（II）催化的环化前体与2-脱氧d -核糖衍生物的偶联反应，在温和条件下合成了Origo糖精。该方法将为包括碳水化合物合成在内的有机合成提供有力的工具。少