硅卡宾铁(0)氮气配合物催化的炔烃选择性硼氢化反应

硅卡宾(R2Si?, silylene)是卡宾的相似体,可以作为配体与金属形成配合物.由于硅的原子半径比碳大,硅卡宾可与Lewis碱配位形成三配位甚至四配位的化合物同时保持很强的配位能力.因此,硅卡宾兼具卡宾和膦配体的结构特征,在稳定新颖的金属配合物及均相催化领域或具有更大的调控空间.本工作报道硅卡宾铁氮气配合物[Ph C(t-Bu N)2Si CH2C(t-Bu)NAr]FeN2(D,Ar=2,6-(i-Pr)2C6H3)催化的炔烃的选择性硼氢化反应.研究发现,该配合物对炔烃的硼氢化反应具有很好的区域及立体选择性,主要生成E式构型产物并表现出很好的官能团耐受性.该研究表明,硅卡宾对过渡金属催化具有很好的调控作用,具有很好的研究潜力.     

氮杂环卡宾氯化亚铜催化对称内炔烃硼氢化反应

本文报道了惰性对称内炔烃硼氢化反应,高效合成系列硼酸酯化合物。以氮杂环卡宾氯化亚铜催化联硼酸频哪醇酯与对称内炔烃发生反应,生成烯基铜试剂,再经甲醇质子化,高效合成了构型单一的顺式烯基硼酸酯,产物经~1H NMR、~(13)C NMR、HRMS表征。系统考察了反应各项参数,讨论了反应可能的历程。本研究的炔烃硼氢化方法简便高效,催化剂稳定,无需使用膦配体,环境友好。     

联吡啶配体促进铬催化炔烃的顺式硼氢化反应（英文）

报道了金属铬催化炔烃的硼氢化反应.廉价易得的三氯化铬在4,4’-二叔丁基-2,2’-联吡啶配体及单质镁的还原作用下表现出高反应活性,催化实现了频哪醇硼烷与炔烃加成的硼氢化反应,为室温条件下制备烯基硼化合物提供了一条有效的合成策略.     

硼桥联三氮杂环卡宾配位的铁分子氮配合物:合成、表征和反应性质研究

研究了氮上取代基为1-金刚烷基的苯基硼桥联三氮杂环卡宾配体在铁促进的氮气活化转化反应中的应用.通过苯基硼桥联三氮杂环卡宾亚铁氯化物[PhB（AdIm）₃FeCl]（1）在氮气氛下与KC₈反应合成了一价铁分子氮配合物[PhB（AdIm）₃Fe（N₂）]（2）.进一步通过2与KC₈和18-C-6的反应合成了零价铁分子氮配合物[K（18-C-6）（THF）]-[PhB（AdIm）₃Fe（N₂）]（4）.这些配合物均通过核磁共振、紫外吸收光谱、红外光谱、元素分析等表征,其中配合物2和4的结构经单晶X射线衍射表征确定.配合物2和4的N-N伸缩振动频率分别为1928和1807 cm^－1,均为同价态铁末端分子氮配合物最低值.在过量KC₈和Me₃SiCl存在下,配合物1,2和4均可催化N₂的还原硅基化反应,生成N（SiMe₃）₃.催化体系的TON可达87.     

水溶性氮杂环卡宾钯金属配合物催化的Sonogashira反应

成功合成了一种磺酸钠基团官能团化的水溶性氮杂环卡宾钯金属配合物。在无膦、以水作溶剂的反应条件下,这种水溶性卡宾钯金属配合物能高效催化碘代芳烃和端基炔烃的Sonogashira偶联反应,反应结束后,可以通过萃取的方式把催化剂从反应混合物中分离出来,该催化剂可以重复循环使用四次。     

Au(Ⅰ)配合物催化剂室温高效催化炔烃水合反应

合成了一系列(1,1'-联苯)-2-二(1-金刚烷基)磷配体, 并制备出8种相应的Au(Ⅰ)配合物. 以甲醇为溶剂, 在6-十二炔水合反应中考察了8种Au(Ⅰ)配合物的催化性能, 结果表明, 以含有3'-(吡咯-1-羰基)官能团的Au(Ⅰ)配合物为催化剂时, 其用量仅需炔烃用量的0.1%~0.3%(摩尔分数), 室温下即可高效地催化炔烃进行水合反应.     

Pt(DVDS)-Phan催化的末端炔烃的硅氢加成反应

以Pt(DVDS)-Phan体系作为末端炔烃与三乙基硅烷或三苯基硅烷进行硅氢加成的催化剂, 除三甲基硅乙炔与三乙己硅烷反应外, 其余反应的收率均高于90%, 并且高选择性地或唯一地得到马氏加成产物或者反马氏反式加成产物, 立体选择性或区域选择性超过95%.     

锆、钛介导的烯烃、炔烃硼氢化（英文）

过渡金属催化的烯烃、炔烃硼氢化反应是制备硼酸酯类化合物最为有效的方法之一,该反应具有100%的原子经济性,原料简单易得,产物多样性可调等优点.已知的金属催化剂大都依赖于铑、铱、钯、铂、钴、铁、铜等后过渡金属,而使用前过渡金属锆、钛作为催化剂的反应体系则鲜有报道.总结了锆、钛介导的(化学计量与催化量)烯烃、炔烃硼氢化反应的研究现状,并对今后锆、钛催化的烯烃、炔烃硼氢化反应的发展进行了展望.     

过渡金属催化下的烯烃硼氢化反应

本文综述了在过渡金属尤其是铑络合物催化下烯烃与CB的硼氢化反应在化学、位置和立体选择性的进展,对它们的机理也进行了讨论。     

Dinitrogen Activation Upon Reduction of a Triiron(II) Complex

Reaction of a trinuclear iron(II) complex, Fe₃Br₃ L ( 1 ), with KC₈ under N₂ leads to dinitrogen activation products ( 2 ) from which Fe₃(NH)₃ L ( 2‐1 ; L is a cyclophane bridged by three β‐diketiminate arms) was characterized by X‐ray crystallography. ¹H NMR spectra of the protonolysis product of 2 synthesized under ¹⁴N₂ and ¹⁵N₂ confirm atmospheric N₂ reduction, and ammonia is detected by the indophenol assay (yield ～30 %). IR and Mössbauer spectroscopy, and elemental analysis on 2 and 2‐1 as well as the tri(amido)triiron(II) 3 and tri(methoxo)triiron 4 congeners support our assignment of the reduction product as containing protonated N‐atom bridges.     

Catalytic Selective Dihydrosilylation of Internal Alkynes Enabled by Rare-Earth Ate Complex

Hydrosilylation of alkynes generally yield vinylsilanes, which are inert to the further hydrosilylation because of the steric effects. Reported here is the first successful dihydrosilylation of aryl- and silyl-substituted internal alkynes enabled by a rare-earth ate complex to yield geminal bis- and tris(silanes), respectively. The lanthanum bis(amido) ate complex supported by an ene-diamido ligand proved to be the ideal catalyst for this unprecedented transformation, while the same series of yttrium and samarium alkyl and samarium bis(amido) ate complexes exhibited poor activity and selectivity, indicating significant effects of the ionic size and ate structure of the rare-earth catalysts.     

Highly Selective Hydroboration of Alkenes,Ketones and Aldehydes Catalyzed by a Well‐Defined Manganese Complex

Well‐defined manganese complexes based on inexpensive, readily available ligands, 2,2′:6′,2′′‐terpyridine and its derivatives have been prepared and employed for the selective hydroboration of alkenes, ketones and aldehydes. Highly Markovnikov regioselective hydroboration of styrenes as well as excellent chemoselective hydroboration of ketones over alkenes were achieved, for the first time, by an earth‐abundant manganese catalyst.     

A Dinitrogen Dicopper(I) Complex via a Mixed‐Valence Dicopper Hydride

Low‐temperature reaction of the tris(pyrazolyl)borate copper(II) hydroxide [^iPr2TpCu]₂(μ‐OH)₂ with triphenylsilane under a dinitrogen atmosphere gives the bridging dinitrogen complex [^iPr2TpCu]₂(μ‐1,2‐N₂) ( 3 ). X‐ray crystallography reveals an only slightly activated N₂ ligand (N‐N: 1.111(6) Å) that bridges between two monovalent ^iPr2TpCu fragments. While DFT studies of mono‐ and dinuclear copper dinitrogen complexes suggest weak π‐backbonding between the d¹⁰ Cu^I centers and the N₂ ligand, they reveal a degree of cooperativity in the dinuclear Cu‐N₂‐Cu interaction. Addition of MeCN, CNAr^2,6‐Me, or O₂ to 3 releases N₂ with formation of ^iPr2TpCu(L) (L=NCMe, CNAr^2,6‐Me2) or [^iPr2TpCu]₂(μ‐η²:η²‐O₂) ( 1 ). Addition of triphenylsilane to [^iPr2TpCu]₂(μ‐OH)₂ in pentane allows isolation of a key intermediate [^iPr2TpCu]₂(μ‐H) ( 5 ). Although 5 thermally decays under N₂ to give 3 , it reduces unsaturated substrates, such as CO and HC≡CPh to HC(O)H and H₂C=CHPh, respectively.     

Hydroboration of Phosphaalkynes by HB(C6F5)2

The hydroboration of phosphaalkynes with Piers’ borane (HB(C₆F₅)₂) generated unusual phosphaalkenylboranes [RCH=PB(C₆F₅)₂]₂ that persisted as dimers in both solution and the solid state. These P₂B₂ heterocycles underwent ring opening when subjected to nucleophiles, such as pyridine and tert‐butylisocyanide, to yield monomeric phosphaalkenylborane adducts RCH=PB(C₆F₅)₂(L). DFT calculations were performed to probe the nature of the interaction of phosphaalkynes with boranes.     

Catalytic Selective Dihydrosilylation of Internal Alkynes Enabled by Rare‐Earth Ate Complex

Hydrosilylation of alkynes generally yield vinylsilanes, which are inert to the further hydrosilylation because of the steric effects. Reported here is the first successful dihydrosilylation of aryl‐ and silyl‐substituted internal alkynes enabled by a rare‐earth ate complex to yield geminal bis‐ and tris(silanes), respectively. The lanthanum bis(amido) ate complex supported by an ene‐diamido ligand proved to be the ideal catalyst for this unprecedented transformation, while the same series of yttrium and samarium alkyl and samarium bis(amido) ate complexes exhibited poor activity and selectivity, indicating significant effects of the ionic size and ate structure of the rare‐earth catalysts.