二价钌催化的金属卡宾经由的硫叶立德[2,3]-σ重排反应研究

报道烯(炔)基硫醚与α-重氮羰基化合物, 在[RuCl₂(p-cymene)]₂催化下, 经由金属卡宾发生硫叶立德[2,3]-σ重排反应(Doyle-Kirmse反应). 在Ru(II)作用下, α-重氮羰基化合物与烯丙基硫醚的反应以较好收率生成相应的[2,3]-σ重排产物高烯丙基硫醚. 同样条件下与炔丙基硫醚的反应则生成[2,3]-σ重排产物联烯和呋喃衍生物, 后者是联烯进一步在Ru(II)作用下重排的产物.     

磷杂环戊二烯[1,5]-σ键迁移的新进展

磷杂环戊二烯在探索磷化学的研究中发挥了重要的作用,并广泛应用于配位化学、催化和有机光电材料等领域.[1,5]-σ键迁移(以下简称[1,5]迁移)是磷杂环戊二烯的一类重要反应.该迁移主要是由于磷杂环戊二烯弱的芳香性和环外磷上取代基的σ键与环内二烯体的反键轨道存在一定的σ-π*超共轭效应等特性所共同造成的.该反应自发现以来就成为磷杂环戊二烯衍生化的重要和有效手段.主要介绍了近几年来人们利用磷杂环戊二烯[1,5]迁移特性设计与合成新型有机磷化合物和含磷光电材料的研究进展.     

[2,3]σ键迁移重排立体选择性的Huckel-Hubbard理论研究

本文提出一种确定Huckel-Hubbard(H-H)参数的方法,并将H-H 理论首次推广用于Witting重排,硫叶立德重排,烯丙基亚砜重排等[2,3]σ键迁移重排反应的研究.我们考虑协同机理,构造了Huckel和Mobius 两种不同反应途径的基态和低激发态势能面,详细讨论了热反应和光化学反应的立体选择性和反应的活化能     

羟胺衍生物的[3,3]σ迁移反应及其应用

[3,3]σ迁移反应作为有机化学中的经典反应,自发现以来,反应类型不断扩大,且一直广泛应用于有机与药物合成等领域.因为羟胺衍生物的N-O键强度较弱,较易断裂,[3,3]σ迁移反应在较为温和的条件下即可进行,得到含有羟基和氨基的复杂分子,近年来,该类反应引起越来越多的关注.综述了羟胺衍生物的[3,3]σ迁移反应,包括N-...     

己二烯基烯丙基醚的Wittigσ迁移重排反应

烯丙基醚类的[2.3]Wittig σ迁移重排反应是近几年来新发展的一个有机合成反应。由于此反应具有高度的非对映选择性和立体选择性,它为合成中的碳链延伸、立体选择性反应及不对称合成提供了一个新的方法,因为此反应可通过选择底物的几何构型和取代基得到立体选择性产物。[2.3]Wittig σ迁移重排     

多烯化合物的Cope重排反应:[5,5]σ迁移、串联[3,3]σ迁移与自由基重排机理

介绍戊二烯基苯基醚和1,3,7,9-癸四烯衍生物重排反应的机理。戊二烯基苯基醚的重排反应是经过[5,5]和串联的[3,3]σ迁移反应双途径进行的;而1,3,7,9-癸四烯衍生物重排反应既可以经过[5,5]和串联的[3,3]σ迁移反应双途径进行,也可以经过自由基机理进行。     

含手性碳原子的[3,3]σ迁移反应的立体化学过程

本文对含有手性碳原子的［３，３］σ迁移反应的立体化学过程进行了讨论，重点讨论了含有手性碳原子的Ｃｏｐｅ重排和Ｃｌａｉｓｅｎ重排的产物及其生成的立体化学过程。     

吡咯并[2,3-d]嘧啶衍生物的合成方法研究进展

归纳总结了2,4-二氨基吡咯并[2,3-d]嘧啶和2-氨基-4-氧代吡咯并[2,3-d]嘧啶的主要合成方法,并对各方法的优缺点进行了简要评述.参考文献30篇.     

5,6-二甲氧基-N-[(R)-4-甲氧基-2-(丙烯-2-基)-2,3-二氢苯并呋喃-5-基]-1,1a,2,7b-四氢环丙并[c]苯并吡喃-7b-基甲酰胺的合成与表征

鱼藤酮与氧硫叶立德反应得到关键中间体(5,6-二甲氧基-1,1a,2,7b-四氢环丙并[c]苯并吡喃-7b-基)[(R)-4-羟基-2-(丙烯-2-基)-2,3-二氢苯并呋喃-5-基]甲酮(2),2再通过醚化、肟化、贝克曼重排得到5,6-二甲氧基-N-[(R)-4-甲氧基-2-(丙烯-2-基)-2,3-二氢苯并呋喃-5-基]-1,1a,2,7b-四氢环丙并[c]苯并吡喃-7b-基甲酰胺(5),化合物的结构经1H NMR,MS和元素分析确认,采用单晶X射线衍射法确定化合物5的晶体结构.化合物5属于三斜晶系,P1空间群,晶胞参数:a=0.95772(5)nm,b=1.06591(6)nm,c=1.30112(7)nm,α=111.8460(10)°,β=109.8870(10)°,γ=93.0870°,V=1.13429(11)nm3,Z=2,Dc=1.281 g/cm3,μ(Mo Kα)=0.092 mm-1,F(000)=464.     

Catalytic Asymmetric [ 2,3 ] -Sigmatropic Rearrangement of Sulfur Ylides Generated from Carbenoids

The catalytic asymmetric reactions of oxygen or sulfur ylides generated from carbenoids have attracted consider able attention in recent years. High enantioselectivities have been achieved in the 1,3-dipolar cycloaddition reactions and [ 2,3 ]-sigmatropic rearrangement of oxygen ylides. In contrast to the oxygen ylide, the corresponding catalytic asymmetric reaction of sulfur ylide is less developed. Compared to oxygen ylides, the sulfur ylides are more stable and experimental evidence supports a free ylide rather than a metal-bound ylide as reaction intermediate. That means the enantio-control must be in the step of the ylide formation. If the subsequent reaction such as [ 2,3 ]-sigmatropic rearrangement or 1,3-dipolar cycloaddition is a concerted process and is faster than the racemization of the chiral ylide intermediate, then the catalytic asymmetric sulfur ylide reaction will be possible.     

New [2,3]-Sigmatropic Rearrangement of Allylsulfinylcarbanions

Russian Journal of Organic Chemistry -     

Catalytic Asymmetric[2,3]-Sigmatropic Rearrangement of Sulfur Ylides Generated from Carbenoids and Allenic 2-Methylphenyl Sulfide

The first investigation on catalytic asymmetric [2, 3]-sigmatrop-ic rearrangement of sulfur ylides generated from carbenoids andallenic phenyl sulfide was carried out. Up to 55% ee value wasobtained.     

Enantioselective Intramolecular [2,3]-Sigmatropic Rearrangement of Aldehydes via a Sulfonium Enamine Intermediate

The rearrangement of sulfur-containing aldehydes by using a sulfonium enamine intermediate as a formylcarbene mimetic is reported. This is an enantioselective, organocatalytic [2,3]-sigmatropic rearrangement enabling chiral cyclic sulfides bearing an α-quaternary chiral center to be prepared in high optical purity. The enantioselectivity is controlled with a cooperative organocatalyst pair consisting of a chiral amine and a chiral phosphoric acid (CPA). The synthetic versatility of this method is demonstrated by its rapid access to structurally diverse chiral spiro S-heterocycles.     

Synthesis of Conjugated Diallenes by Double [2,3]-Sigmatropic Rearrangement of Conjugated Diyne Trichloromethanesulfenates

The preparation of several 2,4-diyne-l,6-diols and their esterification with trichloromethanesulfenyl chloride is described. The thus generated bis-propargylic trichloromethanesulfenates undergo spontaneous double [2,3]-sigmatropic rearrangement which leads to the formation of conjugated diallenic trichloromethyl sulfoxides in good to excellent yields.     

Photochemical,Metal-Free Sigmatropic Rearrangement Reactions of Sulfur Ylides

Sigmatropic rearrangement reactions constitute one of the most fundamental reactions of carbenes. While state-of-the-art synthetic methods require the use of expensive precious metal catalysts, the application of visible light for the photolysis of α-aryldiazoacetates is much less investigated and provides an operationally simple entry to carbenes under mild reaction conditions. Herein, we report on blue-light induced sigmatropic rearrangement reactions of sulfur compounds with α-aryldiazoacetates. This process, depending on the substitution pattern of the sulfide, opens up formal insertion reactions of carbenes into S−N, S−C, or C−H bonds.     

[3,2]-Sigmatropic Rearrangement of Acyloxy Nitronic Acids into Geminal Acyloxy Nitroso Compounds

Acylation of secondary nitroalkanes is accompanied by [3,2]-sigmatropic rearrangement of acyloxy nitronic acids into geminal acyloxy nitroso compounds which are formed in preparative yields.