導(dǎo)向基團(tuán)輔助金屬催化C-H鍵官能團(tuán)化的理論研究
本文選題:過渡金屬 + 含氮雜環(huán)化合物 ; 參考:《暨南大學(xué)》2016年碩士論文
【摘要】:過渡金屬催化Csp~2-H鍵官能團(tuán)化合成含氮雜環(huán)類化合物已被廣泛研究,但是實(shí)現(xiàn)區(qū)域選擇性的碳?xì)滏I活化還是一個(gè)重大的挑戰(zhàn)。盡管不同的碳?xì)浠罨J降拇呋磻?yīng)均有報(bào)道,配位導(dǎo)向的碳?xì)浠罨磻?yīng)是目前報(bào)道最多的方法之一。但是,其理論研究的發(fā)展稍顯滯后,反應(yīng)機(jī)理的很多細(xì)節(jié)問題尚不明確。在本文中,主要采用了密度泛函理論(DFT)對(duì)Pd/Rh過渡金屬配合物催化C-H鍵選擇性斷裂及Cu催化C-H鍵胺化反應(yīng)機(jī)理進(jìn)行詳細(xì)的理論研究。在第三章中,用密度泛函理論(DFT)B3LYP方法對(duì)1,2,3-三氮唑?qū)虻腜d催化Csp~2-H鍵官能團(tuán)化的反應(yīng)機(jī)理進(jìn)行了系統(tǒng)的理論研究。Pd(OAc)2催化Csp~2-H鍵活化反應(yīng)的取代與環(huán)化機(jī)理的競(jìng)爭(zhēng)反應(yīng)。計(jì)算結(jié)果表明TAA和TAPy體系環(huán)化機(jī)理反應(yīng)的步驟為:(1)Pd(II)通過CMD機(jī)理活化C-H鍵;(2)Pd(II)中間體被PhI(OAc)2氧化為Pd(III)的中間體;(3)Pd(III)下進(jìn)行亞氨基去質(zhì)子化;(4)C-N鍵還原消除。取代路徑的機(jī)理為:(1)Pd(II)通過CMD機(jī)理活化C-H鍵;(2)Pd(II)中間體被PhI(OAc)2氧化為Pd(III)的中間體;(3)在Pd(III)下,通過5元環(huán)過渡態(tài)進(jìn)行C-O鍵連接。當(dāng)TAA作為定位基時(shí),反應(yīng)趨向于環(huán)化產(chǎn)物;恰恰相反,當(dāng)TAPy作為定位基時(shí),反應(yīng)傾向于取代產(chǎn)物。對(duì)于TAPy體系傾向于形成取代產(chǎn)物的原因在于TAPy這一定位基中的吡啶作為一個(gè)配體與Pd作用,使得醋酸根一直是以單配的形式存在,比TAA作為定位基時(shí),少一個(gè)鍵的斷裂過程。在第四章中,采用密度泛函理論M06的計(jì)算方法對(duì)Rh(III)催化N-O取代的苯甲酰胺與1,6-烯炔環(huán)己二烯酮反應(yīng)的機(jī)理進(jìn)行了系統(tǒng)的理論研究。詳細(xì)探討了-OPiv和-OMe兩種取代基進(jìn)行芳基環(huán)化的不同機(jī)理。兩種不同的取代基的反應(yīng)路徑中,最初的亞氨基去質(zhì)子化、通過CMD機(jī)理實(shí)現(xiàn)C-H鍵活化和1,6-烯炔的插入是相同的,之后,由于不同取代基得到的7元環(huán)中間物的不同,導(dǎo)致隨后的反應(yīng)遵循不同的反應(yīng)機(jī)理。當(dāng)-OPiv作為取代基時(shí),高穩(wěn)定性的7元環(huán)中間物將有效的增高?-邁克爾加成路徑的能壘,因此阻止其發(fā)生;當(dāng)-OMe作為取代基時(shí),不穩(wěn)定的7元環(huán)中間物極易與環(huán)己二烯酮中的雙鍵作用,而這利于?-邁克爾加成路徑的發(fā)生。其中,?-邁克爾加成從7元環(huán)開始,會(huì)得到Rh(I)的中間物,如果先進(jìn)行N-O鍵的斷裂,即Rh(III)→Rh(V),不利于反應(yīng)的進(jìn)行。而?-邁克爾加成反應(yīng)中Rh始終保持三價(jià)。在第五章中,用密度泛函方法(DFT)B3LYP方法研究Cu(II)催化合成吡啶并[1,2-a]苯并咪唑反應(yīng)的機(jī)理。設(shè)計(jì)了5種可能的反應(yīng)途徑:(1)首先C-H鍵斷裂,然后亞氨基去質(zhì)子化,最后還原消除(路徑a);(2)首先亞氨基去質(zhì)子化,然后C-H鍵斷裂,最后還原消除(路徑b);(3)首先C-H鍵斷裂,然后C-N鍵形成,最后亞氨基去質(zhì)子化(路徑c);(4)anti-imino-cupration機(jī)理(路徑d);(5)傅-克烷基化反應(yīng)機(jī)理(路徑e)。計(jì)算表明路徑a最可能發(fā)生,即首先發(fā)生C-H鍵活化,然后在三重態(tài)上亞氨基去質(zhì)子化,最后還原消除。
[Abstract]:Transition metal catalytic synthesis of nitrogen-containing heterocyclic compounds by functionalization of Csp-2-H bonds has been extensively studied, but the realization of regioselective activation of carbon-hydrogen bonds is still a major challenge. Although catalytic reactions in different hydrocarbon activation modes have been reported, ligand oriented hydrocarbon activation is one of the most widely reported methods. However, the development of theoretical research is slightly lagging behind, and many details of the reaction mechanism are still unclear. In this paper, density functional theory (DFT) is used to study the mechanism of C-H bond selective fracture catalyzed by PD / Rh transition metal complexes and Cu catalyzed C-H bond amination reaction in detail. In chapter 3, the mechanism of the catalytic functionalization of Csp-2-H bond catalyzed by PD was systematically studied by using DFTFT-B3LYP method. The competitive reaction between the cyclization mechanism and the substitution of the Csp-2-H bond activation reaction catalyzed by PdN OAc2 was studied systematically by DFTFT-B3LYP method. The calculated results show that the cyclization mechanism of TAA and TAPy system is as follows: 1 / 1 / Pd2) the intermediate is activated by the CMD mechanism. The intermediate is oxidized by PhIOOAc2 to the intermediate of PdPy III) by deprotonation of the iminodium and the reduction of the C-N bond by deprotonation. The mechanism of the substitution path is that the C-H bond is activated by the CMD mechanism. The intermediate is oxidized by PhIOAc2 to PdOIII) and the C-O bond is connected by the transition state of the five-member ring. The reaction tends to cyclization product when TAA is the locus group, but on the contrary, when TAPy is the locus group, the reaction tends to replace the product. For the TAPy system, the reason for the formation of the substitution product is that the pyridine in the TAPy site acts as a ligand with PD, which makes the acetate radical always exist in the form of monozygosity, which is one less bond breaking process than that of the TAA system. In chapter 4, the mechanism of the reaction of N-O-substituted benzamide with 1-butene cyclohexadienone was systematically studied by density functional theory (DFT) M06. The different mechanisms of aryl cyclization of -OPiv and -OMe substituents are discussed in detail. In the reaction paths of two different substituents, the initial iminodization, the activation of C-H bond by CMD mechanism and the insertion of 1-hexene, are the same. After that, due to the different substituents, the intermediate of 7-member ring is different. The subsequent reactions follow different reaction mechanisms. When -OPiv acts as the substituent, the highly stable intermediate of the 7-member ring effectively increases the energy barrier of the Michael addition path, thus preventing it from occurring, and when -OMe is used as the substituent, The unstable 7-member ring intermediates are easy to interact with the double bonds in cyclohexadienone, which is conducive to the occurrence of the N-Michael addition path. The intermediate of Rhn I will be obtained from the addition of 7 element ring. If the N-O bond is broken first, that is, Rhn II I) RhN V _ (+), it will be unfavorable to the reaction. In addition, Rh remained trivalent in the addition reaction. In chapter 5, the mechanism of the synthesis of pyridino [1o 2-a] benzimidazole catalyzed by CuPII was studied by density functional method (DFT) and B3LYP method. Five possible reaction pathways were designed: first, C-H bond breaks, then iminamine-deprotonation, and finally reductive elimination (path A ~ (2) first, then C-H bond fracture, finally reductive elimination (path BX ~ (3) first C-H bond fracture. Then the C-N bond was formed, and finally the mechanism of Friedel-g alkylation (path eau) of the imino-cupration mechanism (path C ~ (4) ~ (4) ~ (-) anti-imino-cupration) was formed. The results show that path a is most likely to occur, that is, the activation of C-H bond first, then the deprotonation of iminodium on the triplet, and finally the reduction and elimination.
【學(xué)位授予單位】:暨南大學(xué)
【學(xué)位級(jí)別】:碩士
【學(xué)位授予年份】:2016
【分類號(hào)】:O621.251
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