铜催化炔烃的双官能团化反应研究进展

炔烃的双官能团化反应近年来受到广大科研工作者的关注,其已经发展为一种简单、高效、原子经济性高,能够同时引入各类不同官能团的重要方法。近年来,许多关于铜催化炔烃的双官能团化反应研究见诸报道。本文针对近年来铜催化炔烃的双官能团化反应的研究进行了归纳与总结。     

烯烃的双官能团化反应研究进展

作为一类重要的有机化学反应,烯烃的双官能团化反应不仅可以经济有效地一步合成多位点反应产物,而且可以将起始原料转化为多种含有生物活性或药物活性的化合物,同时还为构建化学结构的多样性提供了更多的方法,所以发展烯烃的双官能团化反应十分重要.对近十二年来各类烯烃的双官能团化反应进行了综述.主要分为:铜催化的烯烃的双官能团化反应、其它过渡金属催化的烯烃的双官能团化反应以及非金属催化的烯烃的双官能团化反应.同时对该类反应的发展前景进行了展望.     

可见光促进的炔烃的双官能团化反应

炔烃是一类易于制备且来源广泛的化合物,具有很高的反应活性.炔烃的双官能团化反应是一种直接、高效地构建各类有用分子骨架的策略.可见光作为一种绿色、清洁、来源广泛且丰富的能源,近几年在化学领域受到广泛关注,在烯烃的双官能团化等反应中有着重要应用.可见光促进的炔烃双官能团化反应在过去几年也得到了迅猛的发展.本综述从可见光促进的自由基历程,以及可见光促进与过渡金属联用两个方面讨论了可见光促进的炔烃双官能团化反应.可见光催化剂具有独特的单电子氧化还原特性,可与底物发生单电子转移,生成相应的自由基.一方面,各类型自由基如碳(sp~3, sp~2)自由基和杂原子(P, S, N, Se, Br, O)自由基可在可见光促进下生成,与碳碳叁键发生自由基加成反应后,生成的烯基自由基在之后的转化中形成双官能团化产物.自由基加成炔烃策略已被应用于一系列有用分子骨架的构建.然而,该策略在内炔烃及脂肪族炔烃上表现不佳.同时,其区域选择性和立体选择性也尚待提高.作为补充,可见光促进的单电子氧化还原形成1,3-偶极子与炔烃发生环加成反应的策略也在近期得到发展,但该类反应因需要特定的反应前体而受到限制.另一方面,可见光促进的单电子氧化炔烃,进而与亲核试剂反应的方法同样在近期得到发展.该方法为炔烃的双官能团化反应提供了新的思路.然而,炔烃较高的还原电势是该方法尚待解决的一个难题.利用过渡金属配合物可与叁键配位发生环金属化或者插入反应的特性,采用可见光促进与过渡金属联用策略来实现炔烃的双官能团化反应也受到研究者的重视.金属配合物在可见光照射下被活化,活化后的金属物种可与炔烃反应生成烯基金属物种,该物种为炔烃双官能团化的活性中间体.该策略可以高效地转化内炔烃和末端炔烃,同时其产物具有较高的区域选择性.然而,该策略对脂肪族炔烃的转化效率尚待提高,其产物的立体选择性问题仍需要解决.同时,发展地球丰产金属如铁、钴、镍等与可见光共同促进的炔烃双官能团化反应是该策略的发展方向之一.综上,我们总结并介绍了可见光促进的炔烃双官能团化反应.我们相信该类反应的独特的反应历程,温和的反应条件以及反应特性将会吸引更多的科学家投入研究.     

铜催化烯烃的不对称加成硼化反应研究进展

铜催化烯烃的不对称加成硼化是构建手性碳硼键的有效方法,成为近年来有机化学的研究热点之一.从烯烃底物类型及反应类型的角度出发,总结了铜催化的烯烃的不对称加成硼化反应的研究进展.介绍了硼氢化反应及其串联反应以及包含硼化的双官能团化反应,以及以上反应的机理及发展现状,并对今后铜催化烯烃的不对称加成硼化反应的发展方向进行了展望.     

铜催化的芳基炔酮的羟化三氟甲硫基化反应（英文）

近年来通过双官能团化的策略来制备含氟化合物已经成为氟化学研究的热点.报道了一例铜催化的芳基炔酮的羟化-三氟甲硫基化反应来合成相应的含三氟甲硫基的烯醇.铜盐和溶剂对于该反应产率的影响非常关键.在最优条件下,一系列含三氟甲硫基的烯醇以中等到良好的产率被制备出来,并且各种官能团能够在该反应中很好地兼容.     

基于Heck插入策略的钯催化烯烃与α-溴代烷基羰基化合物的烯烃氧化双官能化反应合成吲哚2-酮类化合物

正钯催化Heck偶联反应一般首先经过插入和加成步骤生成含C—Pd键中间体A,最后通过β-H消除来实现钯催化循环.如何利用中间体A中的C—Pd键引入新官能团是有机合成研究难点之一.目前有两种策略:(1)零价钯催化体系下,烯烃与卤代烃反应生成含C—Pd键中间体A,然后与亲核试剂(芳基硼酸,Cl-,CO,烯烃和炔烃等)实现烯烃双官能团化反应;(2)两价钯/氧化剂催化体系下,烯烃与有机金属试剂反应生成含C—Pd键中间体A,然后与亲核试     

铜催化的不对称叠氮和炔烃的环加成反应的研究进展

尽管铜催化的叠氮和炔烃环加成(CuAAC)反应作为点击化学的核心反应得到广泛应用,然而其不对称催化的研究却相对滞后.反应本身虽然不产生手性元素,但是能够通过对具有潜手性的炔烃或叠氮化合物的去对称化以及外消旋叠氮或炔烃化合物的动力学拆分,来不对称催化合成手性叠氮、炔烃和三氮唑类具有重要应用价值的化合物.自2013年首例高对映选择性的CuAAC反应被报道以来,相关研究有了重要进展,并被成功用于中心手性、轴手性和平面手性的构建.概述了不对称CuAAC反应的研究进展,讨论其面临的发展难题和未来的发展空间.     

自催化点击化学:新型基于氮杂卡宾铜配合物的超分枝“click聚合物”的合成与表征（英文）

设计合成和表征了新型叠氮基官能团化的SIPr(2,6-diisopropylphenyl]imidazolin-2-ylidene)氮杂卡宾铜配合物.这种氮杂卡宾铜配合物既可作为反应底物又可作为催化剂进行自催化的叠氮炔烃3+2环加成反应(CuAAC).通过这种配合物与炔烃的简单自催化反应,在常温常压条件下合成出了一种新型的基于氮杂卡宾铜配合物的超分枝"聚合物",并通过固体核磁、红外光谱、元素分析、原子吸收光谱和X射线光电子能谱对其进行了完整的表征.     

金催化去芳构化反应研究进展

均相金催化在过去十几年经历了飞速的发展,展现出了非常高的催化效率和非常强的官能团兼容性.另一方面,催化去芳构化反应能够直接高效地将芳香化合物转化为高度官能团化的具有丰富三维立体结构的分子.因此,金催化去芳构化反应将会为天然产物和复杂分子的合成提供新颖直接高效的路径.本文总结了近几年金催化去芳构化反应的例子,主要可分为金催化的重排反应和炔烃/联烯的氢-官能团化反应两方面,同时还介绍了这两类反应的特点与可能的反应机理.     

自催化点击化学：新型基于氮杂卡宾铜配合物的超分枝“click聚合物”的合成与表征

设计合成和表征了新型叠氮基官能团化的SIPr(2,6-diisopropylphenyl]imidazolin-2-ylidene)氮杂卡宾铜配合物。这种氮杂卡宾铜配合物既可作为反应底物又可作为催化剂进行自催化的叠氮炔烃3 2环加成反应（CuAAC）。通过这种配合物与炔烃的简单自催化反应,在常温常压条件下合成出了一种新型的基于氮杂卡宾铜配合物的超分枝“聚合物”,并通过固体核磁、红外光谱、元素分析、原子吸收光谱和X射线光电子能谱对其进行了完整的表征。     

Palladium-catalyzed one-pot construction of difluorinated 1,3-enynes from α,α,α-iododifluoroacetones and alkynes

A palladium-catalyzed one-pot difunctionalization of alkynes with α,α,α-iododifluoroacetones is introduced for the synthesis of difluorinated 1,3-enynes. The reaction proceeds through the radical addition of RCOCF₂ radical to alkynes and subsequent Sonogashira coupling with the same alkynes to give the 1,3-enyne products with high regio and stereoselectivity.     

Copper-catalyzed oxytrifluoromethylation of unactivated alkenes

A mild, versatile, and convenient method for the efficient oxytrifluoromethylation of unactivated alkenes based on a copper-catalyzed oxidative difunctionalization strategy has been developed. This methodology provides access to a variety of classes of synthetically useful CF(3)-containing building blocks from simple starting materials.     

Copper-catalyzed addition of H-phosphine oxides to alkynes forming alkenylphosphine oxides

We have developed efficient copper-catalyzed additions of P(O)H compounds to alkynes, and the reactions provided the regio- and stereoselective E-alkenylphosphine oxides under catalysis of the commercially available and inexpensive copper catalyst system CuI/ethylenediamine. This finding is the first example of copper-catalyzed hydrophosphinylation of alkynes to synthesize alkenylphosphine oxides.     

Base-Promoted Difunctionalization of Alkynes: One-Pot Synthesis of Polysubstituted Chromones

A transition-metal-free one-pot procedure for the difunctionalization of alkynes by C−C triple bond oxidation and transformation towards chromone derivatives has been developed. It involves cascade reactions for carbonylation of alkynes, base-promoted C−C σ-bond cleavage, and intramolecular cyclization. This procedure provides an efficient protocol for the synthesis of polysubstituted chromones from readily available starting materials.     

Stereoselective Base‐Catalyzed 1,1‐Silaboration of Terminal Alkynes

A base‐catalyzed reaction that enables stereoselective 1,1‐silaboration of terminal alkynes is described. This method not only offers a new strategy to functionalize simple and readily accessible alkynes beyond 1,2‐difunctionalization, but also provides an unconventional atom‐ and step‐economical approach to rapidly and reliably access versatile geminal silylboranes in the absence of transition metals and with exquisite stereoselectivity.     

Recent Advances on the Electrochemical Difunctionalization of Alkenes/Alkynes

Electroorganic synthesis is an emerging area of high impact research in organic chemistry, which is considered as one of the green and efficient methods and attracts growing research attention. In this review, we summarized comprehensively the recent literature reports on the electrochemical oxidative difunctionalization of unsaturated C—C bonds. The reaction types described in this review included electrochemical intermolecular cyclization, electrochemical intramolecular cyclization, and electrochemical difunctionalization of alkenes/alkynes. This review focuses on the discussion of its synthetic generality for the preparation of functionalized compounds and the related electrochemical oxidative reaction mechanism.     

Difunctionalization of Alkenes and Alkynes via Intermolecular Radical and Nucleophilic Additions

Popular and readily available alkenes and alkynes are good substrates for the preparation of functionalized molecules through radical and/or ionic addition reactions. Difunctionalization is a topic of current interest due to its high efficiency, substrate versatility, and operational simplicity. Presented in this article are radical addition followed by oxidation and nucleophilic addition reactions for difunctionalization of alkenes or alkynes. The difunctionalization could be accomplished through 1,2-addition (vicinal) and 1,n-addition (distal or remote) if H-atom or group-transfer is involved in the reaction process. A wide range of moieties, such as alkyl (R), perfluoroalkyl (R_f), aryl (Ar), hydroxy (OH), alkoxy (OR), acetatic (O₂CR), halogenic (X), amino (NR₂), azido (N₃), cyano (CN), as well as sulfur- and phosphorous-containing groups can be incorporated through the difunctionalization reactions. Radicals generated from peroxides or single electron transfer (SET) agents, under photoredox or electrochemical reactions are employed for the reactions.     

Direct synthesis of β-ketophosphine oxides via copper-catalyzed difunctionalization of alkenes with H-phosphine oxides and dioxygen

A simple copper-catalyzed direct difunctionalization of alkenes with H-phosphine oxides and dioxygen for the synthesis of β-ketophosphine oxides has been developed under mild conditions. The present protocol, which utilizes an inexpensive catalyst, readily available materials, and environmentally benign oxygen source, provides a convenient and cost-effective approach to construct various β-ketophosphine oxides.     

Synthesis of indenes by the transition metal-mediated carboannulation of alkynes

The synthesis of highly substituted indenes has been achieved by three different transition metal-mediated methods. The first method involves the palladium-catalyzed carboannulation of internal alkynes. The second method utilizes a two-step approach, which involves first the palladium/copper-catalyzed cross-coupling of terminal alkynes with appropriately functionalized aryl halides, followed by copper-catalyzed intramolecular cyclization. The third method involves intermolecular palladium-catalyzed arylation of the arylalkynes formed in the first step of the second method.     

Palladium-catalyzed convenient one-pot synthesis of multi-substituted 2-pyrones via transesterification and alkenylation of enynoates

An efficient one-pot protocol for the synthesis of multi-substituted 2-pyrone derivatives from internal alkynes and unactivated alkenes is reported. The methodology involves difunctionalization of internal alkynes by using Pd(II) as a catalyst alongwith X-Phos as ligand via 6-endo transesterification and subsequent alkenylation pathway. Notable features include simple and easily available starting materials, including a range of unactivated alkenes, reduced synthetic steps and mild reaction conditions with high efficiency.