鄰-碳硼炔（1,2-脫氫-鄰-碳硼烷）與烯烴、雙烯、炔烴以及芳烴可以發生[2 + 2]、[4 + 2]環加成反應和ene反應。 雖然其反應效率不高，但這些開拓性反應預示合成功能化碳硼烷化合物的全新策略，而這些結構通常由已知方法卻不能製備。此論文闡述了更為有效的碳硼炔前體（1-I-2-Li-1,2-C₂B₁₀H₁₀）的合成, 並對其兩種共振體顯著差別的反應性質進行研究，在此基礎上發展合成功能化碳硼烷化合物的有效方法。主要發生以下兩類反應：鍵合形式的碳硼炔同烷基苯、苯甲醚和苯乙烯的環加成反應；雙自由基形式的碳硼炔同脂肪族醚和二茂鐵的C-H鍵插入反應。 / 第二章闡述了鄰-碳硼炔與各種烷基取代苯的反應。反應主產物為[4 + 2]環加成反應產物，分離產率介於35%至67%之間。立體因素對產物的區域選擇性起很重要作用。在碳硼炔同甲苯的反應中，我們還分離表徵了芐基C-H鍵插入反應、串聯[4 + 2]環加成反應/homo Diels-Alder反應和串聯ene反應/[2 + 2]環加成反應形成的副產物。AgF的存在不會影響上述反應的產率和產物分佈。 / 第三章闡述了鄰-碳硼炔與苯甲醚的反應。除[4 + 2]加合物外, 反應還生成了形式環插入反應產物環辛四烯並碳硼烷。該產物由[2 + 2]環加成反應產物經熱σ-[3,3]-遷移重排而得到。立體因素對產物的區域和化學選擇性都起很重要作用，同時電子效應也可能對產物的化學選擇性有影響。上述反應形成的環辛四烯並碳硼烷和1,4-加合物分別在高溫分解和酸性條件下重新芳構化形成1-芳基-鄰-碳硼烷。 / 第四章闡述了碳硼炔與苯乙烯及其衍生物的反應。根據乙烯基上的取代基的不同情況，除預想的[2 + 2] 環加成反應與/或ene反應之外，由苯乙烯的環外雙鍵和相鄰的芳基雙鍵構成雙烯組分的環外[4 + 2]環加成反應也有發生。後者形成的中間體特別活潑以至於它們會立即經由雙自由基形式的碳硼炔的拔氫反應引發的1,3-氫遷移或者脫氫反應重新芳構化分別生成 3,4-二氫萘並[1,2]-鄰-碳硼烷和萘並[1,2]-鄰-碳硼烷。 / 第五章闡述了碳硼炔區域選擇性地插入醚基C-H鍵的反應。 在UV光照條件下，前體分子1-碘-n-鋰-1,n-碳硼烷 (n = 2, 7)很容易消除碘化鋰而生成雙自由基形式的碳硼炔。室溫下，它們經拔氫反應、單電子轉移、親核加成等系列反應後以優秀的區域選擇性插入到脂肪族醚的α-C-H鍵而形成α-碳硼烷基乙醚衍生物。該反應為合成含有烷氧基的功能化碳硼烷提供了很好方法。 / 第六章闡述了鄰-碳硼炔與二茂鐵生成二茂鐵基鄰-碳硼烷的芳基C-H鍵插入反應。我們認為，鄰-碳硼炔將二茂鐵的單電子氧化成二茂鐵陽離子對該插入反應至關重要。這一點由鋰化碳硼烷同二茂鐵（III）六氟合磷酸鹽（[(η⁵-C₅H₅)2Fe]⁺[PF₆]⁻）的反應所證實。碳硼烷基自由基陰離子對二茂鐵陽離子的加合物經由自由基誘發的氫遷移或者分子內串聯的單電子轉移/質子化而得到C-H鍵插入反應產物。 / o-Carboryne (1,2-dehydro-o-carborane) is known to undergo [2 + 2], [4 + 2] cycloaddition and ene reaction with alkenes, dienes, alkynes, and aromatics. Though the efficiencies are not high, these pioneering reactions promise a new strategy for generating functionalized carboranes that are not ready to access by known methods. This thesis describes the synthesis of a more efficient precursor to carboryne, 1-I-2-Li-1,2-C₂B₁₀H₁₀, and the exploration of the significantly different reactivities of carboryne in two resonance forms, aiming at the development of efficient methodologies for functional carboranes. There are generally two classes of reactions: cycloaddition reaction of the bonding form with alkylbenzenes, anisoles, and styrenes; C-H bond insertion reaction of the biradical form with aliphatic ethers and ferrocene. / Chapter 2 describes the reaction of o-carboryne with various alkylbenzenes, which affords [4 + 2] cycloadducts as the major products in 35-67% isolated yields. Steric factors play an important role in the regioselectivity. Minor products derived from benzylic C-H bond insertion reaction, annulation reaction, tandem [4 + 2] cycloaddition/homo Diels-Alder reaction, and tandem ene reaction/[2 + 2] cycloaddition are also isolated and characterized in the reaction of carboryne with toluene. The presence of AgF in the above reaction mixture produces no notable changes in the product distributions and yields. / Chapter 3 focuses on the reaction of o-carboryne with anisoles. In addition to [4 + 2] adducts, cyclooctatetraenocarboranes, formal cycloinsertion products, are generated from the [2 + 2] cycloaddition reaction followed by thermal [3,3] sigmatropic rearrangement. Steric factors play important roles in both regio- and chemoselectivity, and electronic factors may also play a role in the chemoselectivity. Both the resulting cyclooctatetraenocarboranes and 1,4-cycloadducts from the above reactions undergo rearomatization rearrangement to give 1-aryl-o-carboranes under pyrolysis and acidic conditions, respectively. / Chapter 4 details the reaction of o-carboryne with styrene and its derivatives. In addition to the expected [2 + 2] cycloaddition reaction and/or ene reaction, an extra-annular [4 + 2] cycloaddition reaction, in which the exocyclic double bond and one of the neighboring aromatic double bonds in styrene consist of the diene component, also takes place, depending on the substituents on the vinyl unit. The resulting [4 + 2] cycloaddition intermediates are so reactive that they immediately undergo rearomatization via either a formal 1,3-hydrogen shift or dehydrogenation initiated by hydrogen abstraction with carboryne in biradical form, to give 3,4-dihydronaphtho[1,2]-o-carboranes and naphtho[1,2]-o-carboranes, respectively. / Chapter 5 presents the regioselective insertion of carborynes into the ethereal C-H bond. The biradical form of carboryne is readily generated via the elimination of LiI from 1-iodo-n-lithio-1,n-C₂B₁₀H₁₀ (n = 2, 7) under UV irradiation. They undergo α-C-H bond insertion with aliphatic ethers through a sequence of hydrogen abstraction, single-electron transfer, and nucleophilic addition, affording α-carboranylated ethers in excellent regioselectivity at room temperature. This serves as a new methodology for the generation of a series of functionalized carboranes bearing alkoxy units. / Chapter 6 addresses an aromatic C-H bond insertion reaction of o-carborynes with ferrocene to give functionalized ferrocenyl o-carboranes. It is suggested that the single-electron oxidation of ferrocene to the electrophilic ferrocenium cation by o-carborynes is crucial for the insertion reaction, which is confirmed by the reactions of lithiocarboranes with ferrocenium hexafluorophosphate. The nucleophilic adducts of the carboranyl radical anions to the ferrocenium species undergo either radical-induced hydrogen shift or tandem single electron transfer/protonation intramolecularly to give the C-H bond insertion products. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Wang, Rixin. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 153-169). / Abstract also in Chinese. / Acknowledgement --- p.I / Abstract --- p.II / 摘要 --- p.IV / Abbreviation --- p.VI / List of Compounds --- p.VIII / List of Figures --- p.XIV / Contents --- p.XVII / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Skeletal Transformation --- p.3 / Chapter 1.2 --- Boron Substitution --- p.6 / Chapter 1.3 --- Carbon Substitution --- p.9 / Chapter 1.4 --- Dehydrogenation to o-Carboryne --- p.13 / Chapter 1.5 --- Our Objectives --- p.19 / Chapter Chapter 2 --- Reaction of o-Carboryne with Alkylbenzenes --- p.21 / Chapter 2.1 --- 1-I-2-Li-1,2-C₂B₁₀H₁₀: A More Efficient Carboryne Precursor --- p.21 / Chapter 2.2 --- Reaction of Carboryne with Alkylbenzenes --- p.23 / Chapter 2.3 --- Summary --- p.35 / Chapter Chapter 3 --- Reaction of o-Carboryne with Anisoles: Cycloinsertion of Carboryne into Aromatic Rings --- p.36 / Chapter 3.1 --- Dearomatization via Cycloaddition Reaction --- p.36 / Chapter 3.2 --- Reaction of Carboryne with Anisoles --- p.38 / Chapter 3.3 --- Rearrangement of Cyclooctatetraenocarboranes and Diels-Alder Adducts --- p.46 / Chapter 3.4 --- Summary --- p.52 / Chapter Chapter 4 --- Reaction of o-Carboryne with Styrenes --- p.53 / Chapter 4.1 --- Diels-Alder Reaction involving Styrenes as Dienes --- p.53 / Chapter 4.2 --- Reaction of Carboryne with Styrenes --- p.55 / Chapter 4.3 --- Summary --- p.67 / Chapter Chapter 5 --- Regioselective Insertion of Carborynes into Ethereal C-H Bonds --- p.68 / Chapter 5.1 --- Reaction of o-Carborynes with Aliphatic Ethers --- p.68 / Chapter 5.2 --- Mechanistic Studies on α-Carboranylation of Ethers --- p.74 / Chapter 5.3 --- A Revisit to Reaction of Previously Reported Carboryne Precursors with Diethyl Ether --- p.80 / Chapter 5.4 --- Summary --- p.81 / Chapter Chapter 6 --- Formal Insertion of o-Carborynes into Ferrocenyl C-H Bond --- p.82 / Chapter 6.1 --- Ferrocene --- p.82 / Chapter 6.2 --- Reaction of Carborynes with Ferrocene --- p.85 / Chapter 6.3 --- Summary --- p.95 / Chapter Chapter 7 --- Conclusion --- p.96 / Chapter Chapter 8 --- Experimental Section --- p.99 / References --- p.153 / Appendix --- p.170 / Chapter I --- Publications Based on the Research Findings --- p.170 / Chapter II --- Crystal Data and Summary of Data Collection and Refinement --- p.171 / Chapter III --- X-ray crystallographic data in CIF (electronic form) --- p.183
| Identifer | oai:union.ndltd.org:cuhk.edu.hk/oai:cuhk-dr:cuhk_328392 |
| Date | January 2012 |
| Contributors | Wang, Rixin., Chinese University of Hong Kong Graduate School. Division of Chemistry. |
| Source Sets | The Chinese University of Hong Kong |
| Language | English, Chinese |
| Detected Language | English |
| Type | Text, bibliography |
| Format | electronic resource, electronic resource, remote, 1 online resource (xviii, 183 leaves) : ill. (some col.) |
| Rights | Use of this resource is governed by the terms and conditions of the Creative Commons “Attribution-NonCommercial-NoDerivatives 4.0 International” License (http://creativecommons.org/licenses/by-nc-nd/4.0/) |
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