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1.
用AM1方法(采用非限制的Hartree-Fock UHF计算)研究取代乙烯CH2=CHR(R=CH3,CHO和CN)与环己-1,3-二烯的热Diels-Alder加成反应,结果表明,反应存在协同途径和两条自由基途径。  相似文献   

2.
由Diels-Alder反应合成新型热稳定性含硅双马来酰亚胺──合成及表征郝建军,江璐霞,蔡兴贤(四川联合大学材料科学与工程学院高分子材料系,成都,610065)关键词双马来酰亚胺,有机硅,Diels-Alder反应,合成,表征采用单体扩链增韧[1]...  相似文献   

3.
用AM1方法(采用非限制的Hartree-FockUHF计算)研究乙烯与环己-1,3-二烯的热Diels-Alder反应。结果表明反应是放热的且存在两条竞争的路径;协同反应的活化能以及双自由反应速度控制步骤的活化能分别为112.667kJ/mol和78.406kJ/mol。  相似文献   

4.
本文综述了近年来有机合成中应用间接途径以达到区域选择性的目的。涉及使用苯硫基、硝基、硼烷基等数种导向基或通过改变底物反应性如亲电性、变为分子内反应等进行具有区域选择性特性的Diels-Alder反应;对于较为典型的导向基:如硅烷基、硼烷基及其络合物的定位特点,金属络合物的导向基作用,以及二硫缩醛等利用形成缩醛在区域选择性的非Diels-Alder反应中的应用亦作了总结。  相似文献   

5.
本文综述了近年来有机合成中应用产接途径以达到区域经济性的目的。涉及使用苯硫基,硝基,硼烷基等数种导向基或通过改变底物反应性如亲电性,变为分子内反应等进行具有区域性特性的Diels-Alder反应;对于较为典型的导向基;如硅烷基,硼烷基等及其络合物的定位特点,金属的络合物的导向基作用,以及二硫缩醛等利用形成缩醛在区域选择性的非Diels-Alder反应中的应用亦作了总结。  相似文献   

6.
本文报道用环加成-芳构化串连反应制备多取代芳香族化合物的方法。将1-氯-2-卤-3-苯硒基-1,3-丁二烯(5)与丁炔二酸二甲酯进行Diels-Alder反应时,能直接生成多取代的芳香族化合物4-苯硒基-5-卤代邻苯二甲酸二甲酯(4)。若用2-卤素-3-苯硒基-1,3-丁二烯(1)与丁炔二酸二甲酯进行Diels-Alder反应,只得到正常的加成产物4-苯硒基-5-卤素-1,4-环己二烯-1,2-二甲酸二甲酯(3),需再用DDQ处理,才得到多取代芳香族化合物(4)。  相似文献   

7.
热可逆共价交联反应及其研究进展   总被引:14,自引:0,他引:14  
梗概评述了环戊二烯(CPD)与双环戊二烯(DCPD)之间Diels-Alder反应的特点,以及将其引作大分子间交联键的思路;以此为基础详细讨论了热可逆共价交联聚合物的分析方法。制备路线,以及利用这一反应目前所达到的研究水平和成就 。  相似文献   

8.
微波技术在有机合成中的应用   总被引:48,自引:1,他引:48  
评述了微波加热技术在有机合物的烃基化,酯化和皂化,磺化,烯烃加成,Diels-Alder缩合,氧化,环化与开环及重排等反应中的应用,参考文献73篇。  相似文献   

9.
总结了存在电荷转移复合物反应的反应历程的研究结果,在Diels-Alder反应和氢负离子转移反应中观测到负的表观活化焓,表明电荷转移复合物是真正的反应中间体。  相似文献   

10.
噻吩及衍生物的微波反应机理研究   总被引:5,自引:0,他引:5  
应用量子化学理论,初步探讨了苯-噻吩协同分离的可能性,利用微波诱导反应提高了选择性,介绍了在复合催化作用下,对Diels-Alder,acylacylation,HydrogenExchange几个基元反应的机理。  相似文献   

11.
Simon J. Shaw 《合成通讯》2013,43(23):4183-4189
The treatment of benzocyclobutenol with a mild base has been investigated. This reaction results in an electrocyclic opening of the cyclobutene to the corresponding o‐quinodimethane, which has been successfully treated with aldehydes and electron‐deficient alkenes to form benzolactols and benzocyclohexenes respectively.  相似文献   

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14.
In situ generated nitro alkenes underwent tandem Michael-Henry and Michael-Michael sequences leading to the ‘one-pot’ formation of 3,4-substituted tetrahydrothiophenes using the commercially available 1,4-dithiane-2,5-diol (the dimer of mercaptoacetaldehyde) or its 4-mercapto-2-butenoates derivatives as suitable bifunctional partners, respectively.  相似文献   

15.
Transfer hydrogenation, alkene metathesis, and alkyne metathesis possess great value to the synthetic chemistry community. One of the key features of these processes is their reversibility, which can be attributed to the presence of the same number and type of functional groups in both the reactants and products, making these reactions isofunctional. These classic reactions have recently inspired the development of novel shuttle and metathesis reactions that offer great promise for synthetic chemistry. This Review describes and systematically categorizes both recent and older examples of shuttle and metathesis reactions other than transfer hydrogenation and alkene/alkyne metathesis.  相似文献   

16.
All in one pot! Radical, radical–ionic, and radical–organometallic MCR are highly convergent processes, representing a useful pathway to molecular and structural diversity (see scheme). This concept article highlights recent developments in the field and shows the potential of the strategy for the economical elaboration of various kinds of organic substrates.

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17.
An efficient ‘one-pot’ synthesis of the title compounds based on a multicomponent domino reaction between imines and 3-nitro-1-propanol methanesulfonate has been developed.  相似文献   

18.
In this contribution, aminocyclobutanes, as well as eight‐membered enamide rings, have been made from N‐vinyl β‐lactams. The eight‐membered products have been formed by a [3,3]‐sigmatropic rearrangement, whereas the aminocyclobutanes have been derived from a domino [3,3]‐rearrangement/6π‐electrocyclisation process. The aminocyclobutanes have been obtained in a highly diastereoselective fashion. The cyclobutane ring system tolerates fusion even if adjacent quaternary centres are present. Systems containing up to four fused rings are readily accessible. The reaction profile has been investigated by using Gaussian 03. This study suggests that two reaction pathways for aminocyclobutane formation are possible. In one pathway the [3,3]‐sigmatropic rearrangement is the rate‐limiting step and in the second pathway the electrocyclisation is rate limiting. Taken together, these reactions should facilitate the construction of fused heterocycles.  相似文献   

19.
Alkynes are one of the most versatile functional groups as synthetic handles. They allow for a direct access to partially or fully substituted alkenes through difunctionalization reactions. A prominently utilized transformation for these sequences is the carbopalladation of alkynes, which can be followed by various termination steps such as aromatizations, dearomatizations, cross‐coupling reactions, or pericyclic processes, amongst others. This Minireview provides an overview of the recent literature published in the field of carbopalladation chemistry, both with a focus on methodology as well as its application in the syntheses of complex molecular scaffolds, natural products, and functional molecules.  相似文献   

20.
Terminal alkenes of the type H2CC(OR1)X, in which R1 is a tertiary alkyl or a 1-cyclopropylethyl group and X=Ph, OSiMe2But, OEt or H, undergo radical-chain reactions with organic halides R2Hal to give carbonyl compounds R2CH2C(O)X.  相似文献   

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