A Novel One‐Step Synthesis of Symmetrical Dialkyl Trithiocarbonates in the Presence of Phase‐Transfer Catalysis

Symmetrical trithiocarbonates were directly obtained, in moderate to excellent isolated yields, by the reaction of various primary, secondary, allylic and benzylic halides or alkyl tosylates with a suspension of granulated KOH and alumina in CS₂ under phase‐transfer catalysis. In this manner, cyclic trithiocarbonates such as 1,3‐dithiolane‐2‐thione can also be prepared without formation of any polymeric by‐products.     

Intramolecular and Intermolecular Schmidt Reactions of Alkyl Azides with Aldehydes

Despite recent advances in the use of alkyl azides in ring expansion reactions of ketones, there has been little work done on the corresponding chemistry of aldehydes. In the present study, the Lewis acid-promoted reactions of alkyl azides with aldehydes were studied in both intermolecular and intramolecular contexts. The intramolecular reactions of azidoalkyl aldehydes in which the azide and carbonyl groups were separated by 2-5 carbons were examined. Although the examples having the shortest tether failed (3-azidopropanals), each of the other systems gave good yields of either NH-substituted lactams (resulting from hydride migration in the initially formed azidohydrin adduct) or formamides (alkyl migration). The product formed was dependent on the chain length of the starting azido aldehyde. The intermolecular reactions were less efficient, requiring TiCl₄ promotion for even moderate yields, and in each case gave mixtures of products resulting from hydride and alkyl migration.     

Aminoazanium of DABCO: An Amination Reagent for Alkyl and Aryl Pinacol Boronates

The aminoazanium of DABCO (H₂N‐DABCO) has been developed as a general and practical amination reagent for the direct amination of alkyl and aryl pinacol boronates. This compound is stable and practical for use as a reagent. Various primary, secondary. and tertiary alkyl?Bpin and aryl?Bpin substrates were aminated to give the corresponding amine derivatives. The amination is stereospecific. The anti‐Markovnikov hydroamination of olefins was easily achieved by catalytic hydroboration with HBpin and in subsequent situ amination using H₂N‐DABCO. Moreover, the combination of 1,2‐diboration of olefins, using B₂pin₂, with this amination process achieved the unprecedented 1,2‐diamination of olefins. The amination protocol was also successfully extended to aryl pinacol boronates.     

Alkyl chains length dependent fluorescence emission and reversible mechanofluorochromism of AIEE-based quinoline derivatives

Five quinoline derivatives containing different alkyl chains (QLACn, n?=?2, 4, 6, 8, 12) were synthesized to investigate the effect of alkyl chains on their photophysical properties. The fluorescent properties of the QLACn were affected by the alkyl chains, which indicated obvious blue-shifting trend and fluorescence emission are alkyl chains length-dependent by grinding-induced spectral shifts (Δλ_MFC). Longer alkyl-length revealed larger Δλ_MFC. Powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) measurements indicated that the transformation between microcrystalline and amorphous states upon external stimuli should be responsible for the observed reversible MFC behavior.     

Copper-Catalyzed Coupling Reaction of Secondary Alkyl 2-Pyridinesulfonates with Alkyl Lithium-Based Reagents

The Cu(OTf)₂-catalyzed alkyl–alkyl coupling reaction of a secondary substrate MeCH(OSO₂Py)CH₂CH₂C₆H₄(4-OMe) with a nBuLi-based reagent prepared by transmetalation with MgBr₂ ⋅ THF₃ in THF produced a coupling product in 74 % yield. The use of soluble MgBr₂ ⋅ THF₃ in THF was required for this reaction. This method was applied to sBuLi and Ph(CH₂)₄Li. In contrast, transmetalation of MeLi with soluble MgCl₂ ⋅ THF₂ in THF produced the Me reagent, which was reactive for the coupling reaction. The reaction proceeded with inversion of the stereogenic carbon. Furthermore, (S)-14-methyloctadecan-2-one, a sex pheromone produced by lichen moths, was synthesized.     

Oxidative Dehydrogenative Silylation‐Alkenation Reaction of Alkyl Aromatics with Silanes

A Cu(OAc)₂/DDQ/DTBP/Py system catalyzed oxidative dehydrogenative silylation‐alkenation tandem reaction of readily available alkyl aromatic compounds with silanes was established. A variety of functionalized alkenyl organosilicon compounds were provided in good to high yields with a total β‐(E) selectivity. The control experiments revealed that the transformation might proceed through a radical pathway.     

Ni‐Catalyzed Cross‐Coupling Reaction: The Direct Synthesis of Symmetrical Disulfanes from Aryl and Primary Alkyl Halides

A novel Ni‐catalyzed cross‐coupling reaction is introduced for the direct synthesis of diaryldisulfanes and dialkyldisulfanes from aryl halides and primary alkyl halides at normal atmospheric conditions, respectively. This one‐pot and domino protocol utilizes only 10 mol% of NiCl₂ as a catalyst and morpholin‐4‐ium morpholine‐4‐carbo‐dithioate as a new, stable, solid, and odorless sulfurating reagent in the presence of ethylene glycol as a cosolvent and bidentate ligand in dimethyl formamide (DMF) at 130°C with good to excellent yields and relatively short time reaction.     

Organic Reactions in Ionic Liquids: A New Method for the Synthesis of Alkyl Aryl Sulfones by Alkylation of Sodium Arenesulfinates with Unactivated Alkyl Chlorides

Abstract

A new method is reported for the synthesis of alkyl aryl sulfones by alkylation of sodium arenesulfinates with unactivated alkyl chlorides using ionic liquid based on 1‐butyl‐3‐methylimidazolium tetrafluoroborate (BmimBF₄) mixed with water (2:1) as reaction media. The ionic liquid can be reused and the procedure gives the sulfones in moderate yields.     

Synthesis of CuI Trifluoromethylselenates for Trifluoromethylselenolation of Aryl and Alkyl Halides

The development of new strategies for synthesis of trifluoromethylthiolate compounds is of considerable importance in pharmaceuticals, agrochemicals, and advanced materials. Accordingly, currently much attention is being devoted to the development of effective methods and reagents for their synthesis. In contrast, considerably less effort has been afforded to the development of preparing C?SeCF₃ bonds. Herein we report a concise route to synthesize a family of copper(I) trifluoromethylselenolate reagents by the reaction of CuI with the Ruppert’s reagent (Me₃SiCF₃), KF, and elemental selenium in the presence of dinitrogen ligands in CH₃CN at room temperature. The reagent [Cu(bpy)(SeCF₃)]₂ was proven to be air‐stable and highly efficient for nucleophilic trifluoromethylthselenolation of a broad range of (hetero)aryl halides and alkyl halides. This method represents a powerful protocol for the construction trifluoromethylselenolate compounds.     

Rate Study of Samarium Diiodide Reduction of Alkyl Halides and 2-Heptanone

Rate constants directly measured from GC-analyzed method for SmI₂ reduction of alkyl halides were obtained. The rates increase in the orders of primary, secondary, tertiary RX and RCl < RBr < RI as expected. 2-Heptanone was chosen as the partner of alkyl halide in the samarium Barbier reaction. In the absence of HMPA, the reaction orders of alkyl halide and ketone were determined as first and zero order, respectively.     

Alkyl halide/tertiary amine as novel initiators for free radical polymerizations of methyl methacrylate,methyl acrylate and styrene

A series of combinations of alkyl halide with tertiary amine such as ethyl α-bromophenylacetate/tris[2-(dimethylamino)ethyl)]amine (αEBP/Me₆TREN), ethyl 2-bromoisobutyrate/triethylamine (EBiB/TEA), and ethyl 2-chloropropionate/N,N,N′,N′,N′′-pentamethyldiethylenetriamine (ECP/PMDETA) have been developed as novel free radical initiators and used for the polymerizations of methyl acrylate (MA), methyl methacrylate (MMA) and styrene (St). The effects of the structure of alkyl halide and tertiary amine on the polymerization of MA were investigated. Gel permeation chromatograph (GPC) and proton nuclear magnetic resonance (¹H NMR) have been utilized to analyze the end group of the obtained poly(methyl acrylate). Electron spin resonance (ESR) spectroscopy was employed to identify the structure of the radicals produced by αEBP/Me₆TREN, and the results indicated that αEBP reacted with Me₆TREN via a single electron transfer (SET) nucleophilic mechanism to produce corresponding ethyl α-phenylacetate radicals which subsequently initiated the polymerization of MA. As both alkyl halide and tertiary amine are commercially available at low cost, non-explosive, and ease of use and storage in comparison with conventional azo, peroxide or persulfate initiators, the combination of alkyl halide and tertiary amine as a free radical initiator is promising for large-scale practical applications.     

乳酸酯氧化脱氢制备丙酮酸酯的研究进展

生物质资源替代化石资源制取燃料和化学品已成为发展可再生能源化工的重要研究方向之一。本文综述了近年来以生物质平台分子乳酸酯为原料制备丙酮酸酯的研究工作,主要涉及的反应包括气相催化反应、液相催化反应和光催化反应。详细讨论了各种类型的催化剂对反应性能的影响;最后,对乳酸酯催化转化制取丙酮酸酯的发展前景进行了展望。     

Organic Reactions in Ionic Liquids: An Efficient Method for Selective S‐Alkylation of 2‐Mercaptobenzothia(xa)zole with Alkyl Halides

Abstract

Ionic liquids based on 1‐butyl‐3‐methylimidazolium hexafluorophosphate (BmimPF₆) and 1‐butyl‐3‐methylimidazolium tetrafluoroborate (BmimBF₄) are used as reusable reaction medium in the selective S‐alkylation of 2‐mercaptobenzothia(xa)zole with alkyl halides in the presence of potassium carbonate. This procedure is convenient, efficient, and generally gives rise to the S‐alkylated product exclusively.     

Oligo(triacetylene) Derivatives with Pendant Long Alkyl Chains

Substituted (E)‐2‐(ethynyl)but‐2‐ene and (E)‐hex‐3‐ene‐1,5‐diyne derivatives 6 and 10 , respectively, were prepared by dicyclohexylcarbodiimide(DCC)‐mediated esterification of tris(dodecyloxy)benzoic acid ( 4 ) with (E)‐2‐[(triisopropylsilyl)ethynyl]but‐2‐ene‐1,4‐diol ( 3 ) and (E)‐2,3‐bis[(trimethylsilyl)ethynyl]but‐2‐ene‐1,4‐diol ( 8 ), respectively, followed by deprotection with Bu₄NF in wet THF (Schemes 1 and 2). Oligomerization reactions of diyne derivative 10 were attempted by treatment with the Hay catalyst in the presence of mono‐alkyne 6 as an end‐capping reagent. Under these conditions, only compound 7 resulting from the homocoupling of 6 (Scheme 1), and polymers of 10 were obtained due to the difference in reactivity of the alkyne groups in 6 and 10 . In contrast, when phenylacetylene was used as the stopper, the oligomerization of 10 afforded a mixture of end‐capped oligomers, from which 11 – 13 were isolated by column chromatography (Scheme 3). The poly(triacetylenes) (PTA) 16 – 18 were prepared in a similar manner starting from diol 8 and stearic acid (Schemes 4 and 5). Whereas the end‐capped monomers and dimers 11, 12, 16 , and 17 with pendant long alkyl chains do not exhibit any liquid‐crystalline behavior, the trimeric derivatives 13 and 18 show mesomorphic properties, thus demonstrating that the poly(triacetylene) backbone can behave as a mesogenic unit.     

A new synthetic route to borane‐terminated isotactic polypropylenes via styrene/hydrogen consecutive chain transfer reaction

This paper discusses a new process of preparing borane‐terminated isotactic polypropylenes (i‐PPs) via in situ chain transfer reaction, which avoids the use of B‐H‐containing chain transfer agent and thus can be carried out with Al‐activated metallocene catalyst under mild reaction conditions. The chemistry centers on a consecutive chain transfer reaction, first to a trialkylborane‐containing styrene derivative, 4‐[B‐(n‐butylene)‐9‐BBN]styrene (B‐styrene), then to hydrogen in the isoselective polymerization of propylene catalyzed by rac‐Me₂Si(2‐Me‐4‐Ph‐Ind)₂ZrCl₂/MAO. The borane‐terminated i‐PP thus obtained keeps the desired properties of a polymeric alkyl‐9‐BBN reagent and was used to initiate radical polymerization of methyl methacrylate (MMA) to prepare i‐PP‐b‐PMMA diblock copolymer. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 539–548, 2006     

Waterproof Alkyl Phosphate Coated Fluoride Phosphors for Optoelectronic Materials

A facile approach for coating red fluoride phosphors with a moisture‐resistant alkyl phosphate layer with a thickness of 50–100 nm is reported. K₂SiF₆:Mn⁴⁺ particles were prepared by co‐precipitation and then coated by esterification of P₂O₅ with alcohols (methanol, ethanol, and isopropanol). This route was adopted to encapsulate the prepared phosphors using transition‐metal ions as cross‐linkers between the alkyl phosphate moieties. The coated phosphor particles exhibited a high water tolerance and retained approximately 87 % of their initial external quantum efficiency after aging under high‐humidity (85 %) and high‐temperature (85 °C) conditions for one month. Warm white‐light‐emitting diodes that consisted of blue InGaN chips, the prepared K₂SiF₆:Mn⁴⁺ phosphors, and either yellow Y₃Al₅O₁₂:Ce³⁺ phosphors or green β‐SiAlON: Eu²⁺ phosphors showed excellent color rendition.     

Radical Hydrodeiodination of Aryl,Alkenyl, Alkynyl,and Alkyl Iodides with an Alcoholate as Organic Chain Reductant through Electron Catalysis

A simple and efficient method for radical hydrodeiodination is reported. The novel approach uses electron catalysis. In situ generated Na‐alcoholates are introduced as radical chain reducing reagents and reactions work with O₂ as cheap initiator. Hydrodeiodination works on aryl, alkenyl, alkynyl iodides and a tert‐alkyl iodide also gets reduced applying the method. Albeit less general, the method is also applicable to the reduction of aryl bromides. The novel reagent is successfully used to conduct typical reductive radical cyclization reactions and mechanistic studies are reported.     

Radical Hydrodeiodination of Aryl,Alkenyl, Alkynyl,and Alkyl Iodides with an Alcoholate as Organic Chain Reductant through Electron Catalysis

A simple and efficient method for radical hydrodeiodination is reported. The novel approach uses electron catalysis. In situ generated Na‐alcoholates are introduced as radical chain reducing reagents and reactions work with O₂ as cheap initiator. Hydrodeiodination works on aryl, alkenyl, alkynyl iodides and a tert‐alkyl iodide also gets reduced applying the method. Albeit less general, the method is also applicable to the reduction of aryl bromides. The novel reagent is successfully used to conduct typical reductive radical cyclization reactions and mechanistic studies are reported.     

Revealing the Interfacial Chemistry of Fluoride Alkyl Magnesium Salts in Magnesium Metal Batteries

Exploring promising electrolyte-system with high reversible Mg plating/stripping and excellent stability is essential for rechargeable magnesium batteries (RMBs). Fluoride alkyl magnesium salts (Mg(OR^F)₂) not only possess high solubility in ether solvents but also compatible with Mg metal anode, thus holding a vast application prospect. Herein, a series of diverse Mg(OR^F)₂ were synthesized, among them, perfluoro-tert-butanol magnesium (Mg(PFTB)₂)/AlCl₃/MgCl₂ based electrolyte demonstrates highest oxidation stability, and promotes the in situ formation of robust solid electrolyte interface. Consequently, the fabricated symmetric cell sustains a long-term cycling over 2000 h, and the asymmetric cell exhibits a stable Coulombic efficiency of 99.5 % over 3000 cycles. Furthermore, the Mg||Mo₆S₈ full cell maintains a stable cycling over 500 cycles. This work presents guidance for understanding structure–property relationships and electrolyte applications of fluoride alkyl magnesium salts.     

A Modified Water-Gas Shift Reaction. The Decomposition of Alkyl Formate in the Presence of Water Using a Ruthenium Carbonyl

Alkyl formates in the presence of water were rapidly decomposed to H₂, CO₂ and the corresponding alcohols using Ru₃(CO)₁₂ and KOAc as catalyst. Based on the hydrogen gas produced, a turnover rate as fast as 8446/h for ethyl formate at 140°C was observed. The catalyst system was also active for the decomposition of other alkyl formates. The rate of decomposition increased both with increasing amount of KOAc and with decreasing number of carbon atom in the alkyl group of the formate. In addition to Ru₃(CO)₁₂, several other transition metal complexes RuCl₃, RuCl₂(PPh₃)₃, Os₃(CO)₁₂, H₂Os₃(CO)₁₀, RhCl₃, and RhCl(PPh₃)₃, were active in the catalytic decomposition of alkyl formates, although their activities varied greatly. The Ru₃(CO)₁₂-KOAc system also catalyzed the reduction of nitrobenzene by HCOOEt-H₂O to aniline in EtOH and to a mixture of N-phenylformamide and N-methyl-N-phenylformamide in HCOOEt. Under coditions the same as for the hydrogenation of nitrobenzene, ethylene styrene and cyclohexenone were reduced to the corresponding alkanes, whereas 1-hexene and 1-octene were isomerized to the corresponding 2-alkene products.