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The effective catalytic activity of organoaluminum compounds for the monohydroboration of carbodiimides has been demonstrated. Two aluminum complexes, 2 and 3, were synthesized and characterized. The efficient catalytic performances of four aluminum hydride complexes L1AlH2 (L1=HC(CMeNAr)2, Ar=2,6‐Et2C6H3; 1), L2AlH2(NMe3) (L2=o‐C6H4F(CH=N‐Ar), Ar=2,6‐Et2C6H3; 2), L3AlH (L3=2,6‐bis(1‐methylethyl)‐N‐(2‐pyridinylmethylene)phenylamine; 3), and L4AlH(NMe3) (L4=o‐C6H4(N‐Dipp)(CH=N‐Dipp), Dipp=2,6‐iPr2C6H3; 4), and an aluminum alkyl complex L1AlMe2 (5) were used for the monohydroboration of carbodiimides investigated under solvent‐free and mild conditions. Compounds 1–3 and 5 can produce monohydroborated N‐borylformamidine, whereas 4 can afford the C‐borylformamidine product. A suggested mechanism of this reaction was explored, and the aluminum formamidinate compound 6 was characterized by single‐crystal X‐ray, also a stoichiometric reaction was investigated. [ABSTRACT FROM AUTHOR]

We report a Cu-catalyzed coupling between triarylaluminum reagents and alkyl halides to form arylalkanes. The reaction proceeds in the presence of N,N,N’,N’-tetramethyl-o-phenylenediamine (NN-1) as a ligand in combination with CuI as a catalyst. This catalyst system enables the coupling of primary alkyl iodides and bromides with electron-neutral and electron-rich triarylaluminum reagents and affords the cross-coupled products in good to excellent yields.

Abstract Metallizing hydrocarbons has received renewed attention as a potential means to increase energy density and burn rate. Particle agglomeration however, is a significant concern, impeding both performance as well as practical implementation due to system fouling. Achieving a metallized hydrocarbon without nanoparticles in suspension would avoid particle agglomeration problems. Previous proof-of-concept work with highly reactive organometallic Al-based clusters stabilized by ligands and dissolved in a hydrocarbon showed such a scheme is not only possible, but the decreased size of the cluster molecules relative to nanoparticles substantially increases reactivity and at least an order of magnitude less active aluminum. To increase understanding of how such burning rate effects manifest with dissolved aluminum, a higher valency alkyl aluminum historically used as a hypergol, triisobutylaluminum (IBu 3 Al), is dissolved in toluene and isolated droplet combustion is characterized showing up to 60% burning rate increase with 810 mM IBu 3 Al relative to that of pure toluene attributed specifically to the aluminum content of the additive molecule. Flame emission spectroscopy observing AlO emission supports the vital role of gas eruption and droplet disruption to transport additives into the flame. [ABSTRACT FROM AUTHOR]

A strong organophosphorus superbase, N‐(diphenylphosphanyl)‐1,3‐diisopropyl‐4,5‐dimethyl‐1,3‐dihydro‐2H‐imidazol‐2‐imine (IAP3) was combined with a sterically encumbered but modestly acidic Lewis acid (LA), (4‐Me‐2,6‐tBu2‐C6H2O)AliBu2 ((BHT)AliBu2), to synergistically promote the frustrated Lewis pair (FLP)‐catalyzed living polymerization of methyl methacrylate (MMA), achieving ultrahigh molecular weight (UHMW) poly(methyl methacrylate) (PMMA) with Mn up to 1927 kg mol−1 and narrow molecular weight distribution (MWD) at room temperature (RT). This FLP catalyst system exhibits exceptionally long lifetime polymerization performance even in the absence of free MMA, which could reinitiate the desired living polymerization after the resulting system was held at RT for 24 h. An immortal FLP system composed of organophosporus superbase and organoaluminum promoted the living polymerization of methyl methacrylate, achieving polymers with medium to ultrahigh molecular weight (Mn up to 1927 kg mol−1) and narrow molecular weight distribution. [ABSTRACT FROM AUTHOR]

Nickel catalyzes the multicomponent coupling reaction of terminal alkenes, carbon dioxide, and organoaluminum reagents, leading to the synthesis of homoallylic alcohols in moderate-to-good yields with excellent regio- and stereoselectivities. [ABSTRACT FROM AUTHOR]

Density functional theory (DFT) calculations were performed to examine the reaction pathway of Ni-catalyzed cross-coupling with organoaluminum through C-O bond cleavage. The results indicate that the strong Lewis acidity of organoaluminums significantly facilitates the transmetalation step, but not the oxidative addition or reductive elimination step. [ABSTRACT FROM AUTHOR]

Fifty-four years after the Nobel Prize was awarded to Karl Ziegler and Giulio Natta for the polymerization of olefins by complex organometallic catalysts, the field continues to elicit enormous interest, both from the academia and the industry. Furthermore, this chemistry and technology occupy a high ground in the annals of 20th-century science. The elegance and simplicity of Ziegler's chemistry continue to astound researchers even today, and the enormous impact this chemistry has had on the quality of our life is truly incredible. Polyethylene, produced using Ziegler's chemistry has touched every aspect of common man's life, so much so that, today it is impossible to imagine life on this planet without polyethylene. Equally fascinating is the story of how Ziegler stumbled on this most impactful discovery. Ziegler's discipline and rigor in systematically following every lead in the laboratory, however trivial it seemed, and his penchant for understanding the basics of science culminated in 1954, with a simple reaction for converting ethylene to polyethylene, the quintessential carbon-carbon (C-C) bond forming reaction. His life and work hold many lessons for all scientists who dream of making their scientific quests useful and relevant to society. It is also relevant to the contemporary debate on basic versus applied research. [ABSTRACT FROM AUTHOR]

A new process for the synthesis of dimethylalkynylaluminum reagents under flow conditions is described. It involves a base-catalyzed alumination of terminal alkynes using a resin-supported organocatalyst. Final organometallic species are obtained in solution, and can further react with various aldehydes or nitrones. [ABSTRACT FROM AUTHOR]

• Solubility of L 1 H (1), L 1 AlI 2 (2) and L 2 AlI 2 (3) in selected pure solvents was determined. • The experimental solubility data were correlated by different thermodynamic models. • The apparent thermodynamic properties and Hansen solubility parameters of dissolution process were calculated. • Hirshfeld surface analysis was used to explain the dissolution behavior of L 1 AlI 2 (2) and L 2 AlI 2 (3) In this work, the solubility of L 1 H (1) (L 1 = HC(CMeNAr) 2 , Ar = 2,4,6-Me 3 C 6 H 2 , molecular weight 334.5) in five pure solvents and the solubility of L 1 AlI 2 (2) (molecular weight 614.29) and L 2 AlI 2 (3) (L 2 = HC(CMeNAr) 2 , Ar = 2,6-Et 2 C 6 H 3 , molecular weight 642.34) in four pure solvents ranging from 268.15 K to 303.15 K were determined by static analysis method.The experimental results showed that the solubility of the three compounds increased with the increase of temperature. At 303.15 K, the order of solubility (102x) of L 1 H (1) was toluene (37.160) > tetrahydrofuran (34.590) > n -hexane (25.527) > ethanol (0.849) > methanol (0.275). The order of solubility (102x) of L 1 AlI 2 (2) is dichloromethane (10.475) > toluene (2.383) > tetrahydrofuran (2.200) > n -hexane (0.352). The order of solubility (102x) of L 2 AlI 2 (3) is dichloromethane (5.836) > toluene (3.607) > tetrahydrofuran (0.829) > n -hexane (0.289). Seven common thermodynamic models are used to correlate experimental solubility data: Apelblat model, Yaws model, polynomial empirical equation, λh model, Wilson model, NRTL model, and UNIQUAC model. Most models fit well, with an average absolute relative deviation (ARD) less than 5 % and an average root mean square deviation (RMSD) less than 0.2 %. Among them, the Apelblat model has a wide range of applicability in terms of empirical models with an average ARD less than 3.5 %. The Wilson model has the best fitting effect in terms of activity coefficient models with an average ARD of 0.538 %. Hirshfeld surface analysis of L 1 AlI 2 (2) and L 2 AlI 2 (3) showed that H···H contact had the highest contact rate between the two compounds. accounting for 65.0 % and 66.0 %, respectively. In addition, Hansen solubility parameters were calculated to account for differences in solubility of L 1 H (1) in different solvents. Finally, the calculation results of the apparent thermodynamic function show that the dissolution process of the three compounds is an entropy-enhancing and endothermic process. The solubility data determined in this paper, the activity coefficient calculated by fitting, and the melting enthalpy can be used as basic chemical data for the synthesis and recrystallization of organoaluminum compounds. [ABSTRACT FROM AUTHOR]

We present a direct cross-coupling reaction between arylaluminum compounds (ArAlMe2·LiCl) and organic halides RX (R=aryl, alkenyl, alkynyl; X=I, Br, and Cl) without any external catalyst. The reaction takes place smoothly, simply upon heating, thereby enabling the efficient and chemo-/stereoselective formation of biaryl, alkene, and alkyne coupling products with broad functional group compatibility. [ABSTRACT FROM AUTHOR]

We present a direct cross-coupling reaction between arylaluminum compounds (ArAlMe2⋅LiCl) and organic halides RX (R=aryl, alkenyl, alkynyl; X=I, Br, and Cl) without any external catalyst. The reaction takes place smoothly, simply upon heating, thereby enabling the efficient and chemo-/stereoselective formation of biaryl, alkene, and alkyne coupling products with broad functional group compatibility. [ABSTRACT FROM AUTHOR]

• Solubility of LH (1) and LAl i Bu 2 (2) in selected pure solvents was determined. • The experimental solubility data were correlated by different thermodynamic models. • The apparent thermodynamic properties of dissolution process were calculated. • Hirshfeld surface analysis was used to explain the dissolution behavior of LAl i Bu 2 (2). Organoaluminum supported by unsymmetrical β -diketimine ligands had special spatial and electronic effects. They were widely used in organic transformation, medicinal chemistry, and catalysis. Surveys the solubility of LH (1) and LAl i Bu 2 (2) in four pure solvents by the static analysis. The solubility data were correlated by seven thermodynamic models. All models demonstrated excellent fitting effect (absolute relative deviation (ARD) < 3 %, root mean square deviation (RMSD) < 0.01 %). For LAl i Bu 2 (2), Hirshfeld surface analysis was used to visualize the intermolecular interactions, and the simulation result showed that H···H contacts dominated major contact interactions. Further, the apparent thermodynamic functions were derived. It showed that, under the experimental conditions, the dissolution process of LH (1) and LAl i Bu 2 (2) was endothermic and entropy-driven. The results of the experiment have important implications for catalytic reactions and purification operations and the design of LH (1) and LAl i Bu 2 (2) in industrial production. [ABSTRACT FROM AUTHOR]

Abstract: An efficient synthesis of 3-hydroxy-3-(alkyl/aryl)indol-2-one derivatives has been described by the reactions of isatin with organoaluminum reagents. The reaction is very rapid and yields are high. The protocol is applicable for substituted isatins as well as a variety of organoaluminums. [Copyright &y& Elsevier]

InternAl delivery: Organoaluminum reagents activate 1,4‐dien‐3‐ones for Nazarov electrocyclization (see scheme), then transfer a substituent to the resulting cyclopentenyl cation with moderate to complete regioselectivity and diastereoselectivity. [ABSTRACT FROM AUTHOR]

The organoaluminum mediated epoxide ring opening of epoxy alcohols is a key step in the oxirane-based approach for polypropionate synthesis. However, this reaction has shown unanticipated regioselectivities when applied to 2-methyl-3,4-epoxy alcohols. In order to gain mechanistic insight into the factors controlling the epoxide ring opening process, diastereomeric 2-methyl-3,4-epoxy alcohols were reacted with triethylaluminum in order to identify the aluminum complexes formed by these systems. Different epoxide-aluminum complexes were calculated using ab initio HF/[13s7p/11s5p] and B3PW91/6-31G** gauge-including atomic orbital (GIAO) methods and compared to the experimental NMR data. The calculated and experimental data correlates with the aluminum dimer complex (TIPSOCH2CH(OAIEt2)CH(CH)3CHCH(O)(AIEt3))2 (VIII) for the systems favoring the nucleophilic attack at the external C4 epoxide carbon, while an unusual trialuminum species TIPSOCH2CH(0AIEt2)CH(CH)3CHCH(0)(AIEt3)2 (X) is consistent with the systems favoring the internal C3 attack. The 27AI NMR data established the tetracoordinated nature of the aluminum metal in all alkoxy aluminum intermediates, while the 13C NMR data provided insight into the aluminum-oxygen coordination. The formation of the complexes was dictated by the stereochemical disposition of the substituents. These complexes are different from the generally accepted bidentate intermediates proposed for 2,3-epoxy alcohols and simpler 3,4-epoxy alcohols. [ABSTRACT FROM AUTHOR]

Abstract: The reactions of organoaluminum reagents (trimethylaluminum, triethylaluminum, etc.) with aryl and alkyl acyl phosphonates, which lead to the formation of α-hydroxy phosphonates in moderate to good yields, are reported. This method provides easy access to secondary and tertiary α-hydroxy phosphonates depending on the reaction conditions. The reactions of triethylaluminum with a series of acyl phosphonates at 0 °C gave the secondary α-hydroxy phosphonates, while at −100 °C they afford the tertiary α-hydroxy phosphonates. [Copyright &y& Elsevier]

The reaction of various aryl bromides with magnesium turnings, LiCl and R2AlCl (R = Et, i-Bu) provides at room temperature arylaluminum reagents in high yields. These organometallic species undergo readily 1,4-additions, acylations, allylations, and Pd-catalyzed cross-couplings with various aryl iodides and bromides. [ABSTRACT FROM AUTHOR]

Dimeric dimethylaluminum compound, {Me2Al[μ-OCH(CH3)CH2OCH3]}2, was synthesized by the reaction of trimethylaluminum and 1-methoxy-2-propanol, an alkoxyalcohol containing asymmetric carbon, and characterized by 1H, 13C, and 27Al NMR spectroscopy. The 1-methoxy-2-propoxodimethylaluminum, as shown by the single crystal structure determination, exists as a dimer in the solid-state in which the ether alkoxide ligand chelates to the aluminum atom. The solution structure was probed by 1H, 13C, and 27Al NMR spectroscopy and the results showed that the five-coordinate isomer is in equilibrium with the four-coordinate isomer. However, variable-temperature 27Al NMR spectroscopy showed only the presence of five-coordinate isomer at -15°C and below. [ABSTRACT FROM AUTHOR]

The Schiff-base compounds 2,4-di-tert-butyl-6-(((3,4,5-trimethoxyphenyl)imino)methyl)phenol (L1H), 2,4-di-tert-butyl-6-(((2,4,6-trimethoxyphenyl)imino)methyl)phenol (L2H), 2,4-di-tert-butyl-6-(((2,4-trimethoxyphenyl)imino)methyl)phenol) (L3H) derived from anilines bearing methoxy substituents have been employed in the preparation of alkylaluminum and zinc complexes. Molecular structure determinations reveal mono-chelate aluminum complexes of the type [Al(Ln)(Me)2] (L1, 1; L2, 2; L3, 3), and bis(chelate) complexes for zinc, namely [Zn(Ln)2] (L1, 5; L2, 6; L3, 7). All complexes have significant activity at 50 °C and higher activity at 100 °C for the ring-opening polymerization (ROP) of ε-caprolactone (ε-CL) with good control over the molar mass distribution (Mw/Mn < 2) and molecular weight. Complex 1 was found to be the most active catalyst, achieving 99% conversion within 18 h at 50 °C and giving polycaprolactone with high molecular weight; results are compared against aniline-derived (i.e., non-methoxy containing) complexes (4 and 8). Aluminum or zinc complexes derived from L1 exhibit higher activity as compared with complexes derived from L2 and L3. Complex 1 was also tested as an initiator for the copolymerization of ε-CL and glycolide (GL). The CL-GL copolymers have various microstructures depending on the feed ratio. The crosslinker 4,4′-bioxepane-7,7′-dione was used in the polymerization with ε-CL using 1, and well-defined cross-linked PCL was afforded of high molecular weight. [ABSTRACT FROM AUTHOR]

TheC NMR spectra of a new class of tri- and tetracyclic organoaluminum and organosulfur bridge-type compounds, containing five-membered heterocycles with an exo-orientation, are discussed. The assignment of the signals and determination of the isomerism of the compounds studied were performed using the spectra of their hydrocarbon analogs, additive calculations, and an analysis of the spectra of products of deuteration and hydrolysis of organoaluminum compounds. [ABSTRACT FROM AUTHOR]

• HAl i Bu 2 catalyzed the hydroacetylenation of carbodiimides with C–C bond formation. • Aluminum complexes have not been reported as catalysts for such reaction. • The catalyst is cheap, non-toxic and environmentally friendly. • Stoichiometric reactions were carried out for the preliminary mechanistic studies. The environmentally friendly and inexpensive organoaluminum compound, diisobutylaluminum hydride (HAl i Bu 2), acts as an efficient pre-catalyst for C-C bond formation by the addition of terminal alkynes to carbodiimides, which is a rare sample that the group 13 complexes to be used for catalyzing such reactions. Preliminary mechanistic studies revealed that the reaction is mainly carried out by initial hydroalumination of carbodiimide and followed by protonolysis with acetylene. A carbodiimide molecule was inserted into the Al-C bond of the generated alkynyl aluminum compound. The final product was obtained by the second protonolysis with acetylene. [Display omitted] [ABSTRACT FROM AUTHOR]

Solvent selection plays a significant role in the purification process and homogeneous reaction. Solubility data is the most intuitive data to reflect the dissolution effect. The solubility of N , N ′ - bis - (salicylaldehyde) ethylenediamine (1) (SalenH 2) and N , N ′ - ethylenebis (salicylideneiminato) methylaluminum (2) (SalenAlMe) in selected solvents was measured from 268.15 K to 318.15 K under an inert atmosphere. All the operations were carried out using standard Schlenk line techniques or in a glove box. The difference in solubility can be attributed to cohesive energy density, polarity, steric hindrance, as well as intermolecular interactions. Van't Hoff equation, Apelblat model, Polynomial equation, NRTL model, Wilson model, and UNIQUAC model were applied for correlating the experimental solubility data. These thermodynamic models were evaluated by the average relative deviation (ARD). Among those, the Apelblat model had wide applicability with an average ARD < 2%. The NRTL model showed the best correlation results for compound 1 in aprotic solvents with an average ARD of 0.74%, and the correlation of the Polynomial equation was significantly greater for compound 2 with an average ARD of 0.71%. The results of model correlation can be used to predict the solubility of compounds 1 and 2. Furthermore, apparent thermodynamic functions were calculated. It was proved that the dissolution process was entropy-increasing endothermic under the experimental conditions. The experiment data would be essential for optimizing purification and recrystallization processes, as well as the design of homogeneous catalysis for compounds 1 and 2 in industry. • Solubility of SalenH 2 and SalenAlMe in selected pure solvents was measured. • Six thermodynamic models were applied for correlating the experimental solubility data. • The apparent thermodynamic properties of dissolution process were calculated. [ABSTRACT FROM AUTHOR]

Regio- and stereospecific alkyl and alkynyl substitution reactions of epoxy selenides with organoaluminum reagents have been developed, which proceed via episelenonium ion intermediates to give the C2 alkyl substitution products with double inversion of the configuration and the C1 alkynyl substitution products with migration of the arylseleno group in high yields, respectively. [Copyright &y& Elsevier]

Microreactor technology has proved to be an important technique in organic synthesis, especially when organometallic compounds are used, because it allows running rapid reactions with reactive and instable intermediates. This review will highlight the preparation of main‐group organometallic compounds deriving from Lithium, Magnesium, Zinc and Aluminum and their applications in flow conditions. [ABSTRACT FROM AUTHOR]