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

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硅定向立体选择性合成烯烃双键羟基加成发生在含羟基乙烯基硅烷的酸催化环化过程中。环化是通过羟基的立体定向同步加成进行的。乙烯基硅烷(Z)-5-硅基-4-戊烯-1-醇，在亚甲基系醚上有一个取代基，能顺利地进行酸催化环化反应，分别生成反式-2,5-、顺式-2,4-和反式-2,3-二取代四氢呋喃，具有中等至高的立体选择性。含氨基乙烯基硅烷的酸催化环化。立体选择性合成吡咯烷在酸性催化剂的作用下，乙烯基硅烷的一个氨基被一个吸电子基团保护，它被顺利地环化成2-（硅甲基）吡咯烷。该环化反应被用于立体选择性合成2，n-dis…More取代吡咯烷（n=3-5）。史无前例的锰介导反应：非稳定羰基基基化合物的生成活性锰以双（氯甲基）醚为前体生成非稳定羰基基化合物，使用锰作为还原剂的该体系，可以在不直接还原亲偶极试剂的情况下实现与缺电子亲和试剂的羰基基化合物的反应。锰酸盐种类：与亲电烷基锰酸盐试剂的生成和反应，“R_3MnLi”与碘甲基硫化物反应生成硫甲基锰试剂，其中锰酸盐作为还原剂而不是烷基化剂。三烷基锰（II）酸盐试剂的还原行为为直接生成一类新的试剂提供了一种方案，即具有不同结构的硫甲基锰试剂，所生成的硫甲基锰试剂可与烯丙基溴、烯酮和醛反应。烯丙基锡烷对1,6-炔的自由基环化反应及以锡烯醇酯为自由基转移剂的新自由基反应[j]。用铜(I)盐催化二硅烷在α，β-烯酮中引入硅基的新方法。二硅烷与Cu(I)盐在非质子极性溶剂中有效地诱导Si-Si键断裂生成硅基亲核试剂，并且在Cu(I)盐的催化量下，其对α，β-不饱和烯酮的1,4加成反应顺利进行。该反应成功地应用于六甲基二硅烷，生成了三甲基硅基亲核试剂，迄今为止不容易获得。本文首次系统地研究了过渡金属a-氰碳离子的c键和n键异构体的结构和反应性。从结构分析、有机金属转化和机理研究等方面阐明了配体的立体化学对其反应性和催化作用的重要作用。通过适当选择反应条件，实现了五羰基钨催化ω-乙基硅烯醚环化反应途径的动态控制，选择性地得到外环或内环产物。少

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