New Generation of Reactive 1,3-Dipole and Radical Reagents and Dynamic Sterocontrol

新一代反应性 1,3-偶极子和自由基试剂以及动态立体控制

基本信息

批准号：
10208203
负责人：
HOSOMI Akira
金额：
$ 35.65万
依托单位：
University of Tsukuba
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research on Priority Areas (B)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

1. Silicon-directed Cyclization of Vinylysilanes : Stereoselective Synthesis of Tetrahydrofurans and TetrahydropyransSilicon-directed stereoselective syn addition of hydroxy group to olefinic double bond occurs intramolecularly in an acid-catalyzed cyclization of vinylsilanes bearing hydroxy group. The cyclization proceeds by stereospecific syn addition of the hydroxy group. Vinylsilanes, (Z)-5-silyl-4-penten-1-ols bearing a substituent on the methylene tether, smoothly undergo the acid-catalyzed cyclization to give trans-2,5-, cis-2,4-, and trans-2,3-disubstituted tetrahydrofurans, respectively, with moderate to high stereoselectivity.2. Acid-Catalyzed Cyclization of Vinylsilanes Bearing an Amino Group. Stereoselective Synthesis of PyrrolidinesIn the presence of an acid catalyst, vinylsilanes bearing an amino group protected by an electron-withdrawing group were smoothly cyclized to 2-(silylmethyl)pyrrolidines. This cyclization was utilized for the stereoselective synthesis of 2,n-dis … More ubstituted pyrrolidines (n=3-5).3. Unprecedented Manganese-Mediated Reactions : Generation of Non-Stabilized Carbonyl YlidsActivated manganese generates nonstabilized carbonyl ylides from bis(chloromethyl) ethers as a precursor, and using this system with manganese as a reductant, the reactions of the ylides with electron-deficient dipolarophiles can be attained without the direct reduction of dipolarophiles by the reductant.4. Manganese Ate Species : Generation and Reactions with ElectrophilesTrialkylmanganese(II) ate reagents, "R_3MnLi" reacted with iodomethylsulfides to produce thiomethylmanganese reagents, where the manganate serves as a reductant not an alkylation agent. The reductive behavior of trialkylmanganese(II) ate reagents provides a protocol for the direct generation of a new class of reagents, thiomethylmanganese reagents with structural variety, and the generated thiomethylmanganese reagents reacted with allyl bromides, enones and aldehydes.5. Radical Cyclization of 1,6-Enynes Using Allylstannanes and New Radical Reactions Using Stannyl Enolates as Radical Transfer Agents6. New Method for Introduction of a Silyl Group into α,β-Enones Using a Disilane Catalyzed by a Copper(I) salt.The reaction of a disilane with a Cu(I) salt efficiently induces cleavage of the Si-Si bond to generate a silyl nucleophile in an aprotic polar solvent and its 1,4-addition to α,β-unsaturated enones smoothly proceeds with a catalytic amount of a Cu(I) salt were found. This reaction is successfully applied to hexamethyldisilane to generate a trimethylsilyl nucleophile, hitherto not easily accessible.7. The first systematic studies on the structure and reactivities of C-and N-bound isomers of transition metal a-cyanocarbanions have been carried out. Strong contribution of stereochemistry of ligands to their reactivities and catalysis has been clarified in view of structural analysis, organometallic transformations, and mechanistic investigations8. Dynamic control of the reaction pathways in the pentacarbonyltungsten catalyzed cyclization of ω-acetylenic silyl enol ethers is achieved giving either exo or endo cyclized product selectively by the appropriate choice of the reaction conditions. Less

1.乙烯基硅烷的硅定向环化：四氢呋喃和四氢吡喃的立体选择性合成在带有羟基的乙烯基硅烷的酸催化环化中，硅定向的羟基与烯属双键的立体选择性顺加成发生在分子内。乙烯基硅烷， (Z)-5-甲硅烷基-4-戊烯-1-醇在亚甲基链上带有取代基，顺利地进行酸催化环化，得到反式-2,5-、顺式-2,4-和反式-2 ,3-二取代四氢呋喃，分别具有中等到高的立体选择性。2．酸催化的带有氨基的乙烯基硅烷的环化。吡咯烷的立体选择性合成在酸催化剂的存在下，带有受吸电子基团保护的氨基的乙烯基硅烷顺利环化为2-(甲硅烷基甲基)吡咯烷，该环化用于立体选择性合成2,n-dis ... 更多取代吡咯烷 (n=3-5).3. 前所未有的锰介导反应：生成不稳定的羰基叶立德活化的锰以双（氯甲基）醚为前体生成不稳定的羰基叶立德，并且使用该体系以锰作为还原剂，叶立德与缺电子亲偶极物的反应无需直接还原即可实现还原剂对偶极菌的影响。 4．锰酸盐的生成及其反应亲电子三烷基锰(II) ate 试剂，“R_3MnLi”与碘甲基硫化物反应生成硫代甲基锰试剂，其中锰酸盐充当还原剂而不是烷基化剂。三烷基锰(II) ate 试剂的还原行为为直接生成新的试剂提供了方案。一类试剂，结构多样的硫甲基锰试剂，以及生成的硫甲基锰试剂与烯丙基溴、烯酮和醛反应。5.使用烯丙基锡烷进行自由基环化以及使用锡烷基烯醇化物作为自由基转移剂将甲硅烷基引入α,β-烯酮的新方法。由铜(I)盐催化的乙硅烷。乙硅烷与Cu(I) 盐在非质子极性溶剂中有效诱导 Si-Si 键断裂，生成甲硅烷基亲核试剂，并且在催化量的 Cu(I) 下，其与 α,β-不饱和烯酮的 1,4-加成顺利进行该反应成功地应用于六甲基二硅烷，生成迄今为止不易获得的三甲基硅基亲核试剂。7．过渡金属α-氰基碳阴离子的C-和N-结合异构体的反应性已经从结构分析、有机金属转化和机理研究的角度阐明了配体的立体化学对其反应性和催化作用的重要贡献8。五羰基钨催化 ω-炔属甲硅烷基烯醇醚环化的反应途径可以得到 exo 或通过选择合适的反应条件选择性地内环化产物。