Iridium-catalyzed [2+2+2] cycloaddition of α,ω-diynes with alkynyl ketones and alkynyl esters

We found that the combination of [Ir(cod)Cl]₂ and rac-BINAP served as an efficient catalyst for the [2+2+2] cycloaddition of 2,7-nonadiyne derivatives and related compounds with alkynyl ketones and alkynyl esters. The corresponding products were obtained in high yields under mild reaction conditions.     

Iodination of organotrifluoroborates: synthesis of vinyl and alkynyl iodides

Vinyl- and alkynyltrifluoroborates are rapidly converted to vinyl and alkynyl iodides under mild conditions using sodium iodide in the presence of chloramine-T. The reaction is stereospecific and proceeds in excellent yield.     

Short and efficient preparation of alkynyl selenides, sulfides and tellurides from terminal alkynes

Diphenyl diselenide reacts with terminal alkynes at room temperature in DMSO in the presence of catalytic amounts of copper iodide to give good to excellent yields of alkynyl phenyl selenides. The reaction occurs under neutral conditions and the solvent acts as the oxidant. Diphenyl disulfide and ditelluride undergo the analogous reaction, but require the presence of a weak inorganic base.     

分光光度法测定微量炔烃的研究

叙述了利用生成炔亚铜的反应来定量测定微量炔烃的分光光度法。研究表明，在严格控制氨的浓度、保持足量的还原剂的条件下，可以有效地消除反应介质、反应时间、反应物的浓度、空气中的氧等对测定的影响，获得满意的定量结果。该方法已在实际生产中得到应用。     

A concise synthetic strategy to alkynyl sulfides via transition-metal-free catalyzed C-S coupling of 1,1-dibromo-1-alkenes with thiophenols

A novel synthetic strategy to alkynyl sulfides via transition-metal-free catalyzed C-S coupling of 1,1-dibromo-1-alkenes with thiophenols has been developed. The new strategy which avoided the transition-metal toxicities is environmental friendly and very important for alkynyl sulfides synthesis.     

Synthesis and reactivity of alkynyl niobocene complexes

The synthesis of alkynyl containing niobocene complexes with differing auxiliary ligands is described. The niobium(III) derivatives of the general formula [Nb(η⁵-C₅H₄SiMe₃)₂(CCR)(L)] where L is either carbonyl, phosphine, phosphite, or isocyanide, were prepared by the reaction of the bis(alkynyl)magnesium reagent with the corresponding cloro-niobocene precursor. In a similar manner the niobium(V) imido compounds, of the general formula, [Nb(=NR′)(η⁵-C₅H₄R″)₂(CCR)], were prepared. The characterization of these complexes is discussed. The reactivity of the alkynyl compounds towards oxidation and protonation has been studied.     

Triphenylphosphine-catalyzed isomerization of alkynyl ketones in aqueous solution

An efficient isomerization of alkynyl ketones to(E,E)-diene ketones was developed.The reaction catalyzed by 20 mol% triphenylphosphine in aqueous media gave the desired products in good yields.     

丁基锡炔基膦酸酯的合成

本文合成了１０个新的二（三）丁基锡炔基膦酸酯「（ｎ－（Ｃ４Ｈ９）ｎＳｎ」ｎ－１Ｏ２Ｐ（Ｏ）Ｃ≡ＣＲ（ｎ＝２,３;Ｒ＝ｎ－Ｃ５Ｈ１１,ｎ－Ｃ６Ｈ１３,Ｐｈ,ＣＨ２ＯＭｅ,ＣＨ２ＯＥｔ）通过元素分析,ＩＲ和＾１Ｈ ＮＭＲ确证了其结构。     

Alkynyl Acylazolium: A Versatile 1,3-Bielectrophilic 3C-Synthon in NHC-Organocatalysis

N-Heterocyclic carbene (NHC) organocatalysis has emerged as a powerful tool in the field of modern organic synthesis especially in the asymmetric construction of various cyclic skeletons. As an emerging NHC-bound 1,3-bielectrophilic intermediate, alkynyl acylazolium has drawn substantial attention in recent years, and has been used as a versatile 3C-synthon in synthesizing valuable organic molecules since its discovery. In this review, focused on the different pathways for the formation of alkynyl acylazoliums from different precursors like alkynoic esters, alkynoic acids and ynals, the recent advances in the transformations and applications of alkynyl acylazoliums pioneered or developed over the last decade under NHC-catalysis were summarized comprehensively. At the same time, the outlook for further investigation and exploration of novel reaction modes for alkynyl acylazoliums in the future was also discussed.     

Unexpected reactivity of pyridinium salts toward alkynyl Fischer complexes to produce oxo‐heterocycles

The unprecedented reaction of ketone‐containing aromatic pyridinium salts 3a ‐ e and alkynyl Fischer complexes 1a ‐ f proceeds via a mild domino process to provide 4,6‐disubstituted pyran‐2‐ones 5a ‐ k and 2,3,5‐trisubstituted furans 6a ‐ h (45‐97%). According of the results of isotopic labeling experiments, a mechanism involving an initial Michael addition appears to be the key step, obtaining a mesomeric structure responsible for the formation of both products.     

Direct cross-coupling of aryl alkynyliodines with arylsulfinic acids leading to alkynyl sulfones under catalyst-free conditions

A facile and efficient one-pot method has been developed for the construction of alkynyl sulfones via direct cross-coupling reaction of aryl alkynyliodines and arylsulfinic acids. The present transformation could be accomplished under catalyst- and additive-free conditions, providing a series of alkynyl sulfones in moderate to good yields with favorable functional group tolerance.     

Alkynyl compounds and nonlinear optics

The authors’ studies of the nonlinear optical (NLO) properties of metal alkynyl complexes are summarized; structure-NLO property relationships are developed and attempts to “switch” optical nonlinearities of alkynyl complexes are described.     

金催化炔基苯并二𫫇英环化合成8-羟基异香豆素的理论研究

Density functional theory（DFT） calculations were carried out on the gold-catalyzed cyclization of alkynyl benzodioxin to 8-hydroxy-isocoumarin reaction to show the molecular mechanism of the reaction. The conclusions obtained from this work are different from those in the previous experimental study. The results show that water molecule acts as both the reactant and the proton shuttle, and promotes the reaction with gold complexes under mild conditions. The nucleophilic addition site of water on the substrate is the C（sp³） atom on the side of the substrate far away from the oxabenzene ring, resulting in C（sp³）—O bond breaking in the substrate. The formation of new C—O bond and the cleavage of C—O bond in the substrate follow a step-by-step mechanism. The oxygen in the side-product acetone comes from the contribution of water in the reaction system. The regioselectivity of the reaction originates from the polarization of alkynyl π-electrons induced by substituents.     

One-Pot Synthesis of Benzodiazepines through RuII-Catalyzed Regioselective [5+2] Annulation of N-Aryl Amidines with Alkynyl Cyclobutyl Acetates

A highly efficient strategy to construct benzo[d][1,3]diazepines via selective C−H bond activation of N-aryl amidines and coupling with alkynyl cyclobutyl acetates was achieved successfully by Ru^II-catalyzed [5+2] cyclization. This protocol features excellent regioselectivity, wide substrate tolerance, mild reaction conditions, which might be potentially applied in the discovery of lead compounds for the developing new drugs.     

Titanocene and zirconocene σ-alkynyl complexes in C---C single bond coupling and cleavage reactions

Group 4 metallocene mono- and bis-σ-alkynyl complexes of the type L₂M(σ-CCR) and L₂M(σ-CCR)₂ with M=titanium and zirconium in the oxidation states +3 and +4 and L=Cp (η⁵-cyclopentadienyl) and Cp^* (η⁵-pentamethylcyclopentadienyl) are important compounds for stoichiometric and catalytic C---C single bond coupling and cleavage reactions. Detailed investigations show five-membered metallacyclocumulenes L₂M(η⁴-1,2,3,4-RC₄R) as the key intermediates in both reactions of a C---C single bond cleavage of different 1,4-substituted 1,3-butadiynes RCC---CCR to alkynyl groups and the opposite reaction of C---C single bond formation starting from alkynyl groups under the formation of 1,4-substituted 1,3-butadiynes. Depending on different metals M and ligands L, coupling or cleavage is favoured. Combination of both reactions offered the first C---C single bond metathesis in homogeneous solution, which is photocatalyzed and titanocene-mediated. It proceeds via titanocene–mono-alkynyl complexes, which are interesting species also for other stoichiometric and catalytic C---C coupling reactions. Some similarities regarding the σ-to-π conversion exist between the coupling of the alkynyl groups at titano- and zirconocenes to complexed 1,3-butadiynes on one side and the coupling of phenyl groups at chromium to complexed diphenyl on the other side.     

Straightforward synthesis of alkynyl imines via 1,2-elimination of α,α-dichloroketimines

Alkylation of α,α-dichloroketimines at the α-position with benzyl bromides afforded β-arylated α,α-dichloroketimines in good yields. The latter imines could be easily transformed to the corresponding alkynyl imines, a synthetically important class of compounds, via 1,2-elimination of HCl upon treatment with 2 equiv of sodium hydride in DMSO or potassium tert-butoxide in THF.     

三苯基锗烯或炔基膦酸衍生物的合成

由三苯基氯化猪与烯或炔基膦酸盐反应,合成了８种新的三苯基锗烯基或炔基膦酸衍生物,利用元素分析,ＩＲ和ＨＮＭＲ表征了这些化合物的结构     

Cesium Hydroxide–Catalyzed Reaction of Terminal Alkynes with Diarylditellurides to Synthesize Alkynyl Tellurides

In the presence of a catalytic amount of cesium hydroxide under an air atmosphere, the reaction of diarylditellurides (1.0 mmol) with terminal alkynes (2.2 mmol) at room temperature exclusively give alkynyl tellurides in good yields.     

Tributylphosphine-catalyzed reaction of ethanethiol with alkynyl ketones

A stereoselective and effective method for the synthesis of vinyl thioethers has been developed.This method is based on the Michael addition of ethanethiol to various alkynyl ketones using 10 mol%of tributylphosphine as catalyst.Most of alkynyl ketones react with ethanethiol in this system to yield mainly Z-isomer of vinyl thioether adducts,only in one case mainly E-isomer of vinyl thioether adducts was observed.     

High extraction ability of 1,3-dialkynyl calixarene towards mercury（Ⅱ） ion

The reaction of 1,3-dipropyn-2-yloxycalix[4]arene with mercury(II)acetate could give mercury-containing alkynyl calixarenepolymer.The extraction behavior of 1,3-dipropyn-2-yl-oxycalix[4]arene towards mercury(II)ion was examined.When the moleratio of Hg~(2 )/calixarene was 1:1,the extractive percent can reach to 99.1%,and the extraction capacity was up to 431 mg/g.It couldalso decrease the Hg~(2 )concentration from 5 to 0.85 mg/L,which was only 17%of the national standard of effluent and satisfied thenational standard of drinking water.The extraction process included chemical reaction.