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Dietmar Stalke - One of the best experts on this subject based on the ideXlab platform.
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meli 4 dem 1 5 and thf 3li3me ntbu 3s how to reduce aggregation of parent mEthyllithium
Chemistry: A European Journal, 2001Co-Authors: Bernhard Walfort, Lutz Lameyer, Regine Herbstirmer, Wilfried Weiss, Rüdiger Bertermann, Joao Rocha, Dietmar StalkeAbstract:: Organolithium compounds play the leading role among the organometallic reagents in synthesis and in industrial processes. Up to date industrial application of mEthyllithium is limited because it is only soluble in diethyl ether, which amplifies various hazards in large-scale processes. However, most reactions require polar solvents like diethyl ether or THF to disassemble parent organolithium oligomers. If classical bidentate donor solvents like TMEDA (TMEDA= N,N,N',N'tetramethyl-1,2-ethanediamine) or DME (DME=1,2-dimethoxyethane) are added to mEthyllithium, tetrameric units are linked to form polymeric arrays that suffer from reduced reactivity and/or solubility. In this paper we present two different approaches to tune mEthyllithium aggregation. In [[(MeLi)4(dem)1,5)infinity] (1; DEM = EtOCH2OEt, diethoxymethane) a polymeric architecture is maintained that forms microporous soluble aggregates as a result of the rigid bite of the methylene-bridged bidentate donor base DEM. Wide channels of 720 pm in diameter in the structure maintain full solubility as they are coated with lipophilic ethyl groups and filled with solvent. In compound 1 the long-range Li3CH3...Li interactions found in solid [[(MeLi)4]infinity] are maintained. A different approach was successful in the disassembly of the tetrameric architecture of [((MeLi)4]infinity]. In the reaction of dilithium triazasulfite both the parent [(MeLi)4] tetramer and the [[Li2[(NtBu)3S]]2] dimer disintegrate and recombine to give an MeLi monomer stabilized in the adduct complex [(thf)3Li3Me-[(NtBu)3S]] (2). One side of the Li3 triangle, often found in organolithium chemistry, is shielded by the tripodal triazasulfite, while the other face is mu3-capped by the methanide anion. This Li3 structural motif is also present in organolithium tetramers and hexamers. All single-crystal structures have been confirmed through solid-state NMR experiments to be the same as in the bulk powder material.
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meli 4 dem 1 5 and thf 3li3me ntbu 3s how to reduce aggregation of parent mEthyllithium
Chemistry: A European Journal, 2001Co-Authors: Bernhard Walfort, Lutz Lameyer, Regine Herbstirmer, Wilfried Weiss, Rüdiger Bertermann, Joao Rocha, Dietmar StalkeAbstract:: Organolithium compounds play the leading role among the organometallic reagents in synthesis and in industrial processes. Up to date industrial application of mEthyllithium is limited because it is only soluble in diethyl ether, which amplifies various hazards in large-scale processes. However, most reactions require polar solvents like diethyl ether or THF to disassemble parent organolithium oligomers. If classical bidentate donor solvents like TMEDA (TMEDA= N,N,N',N'tetramethyl-1,2-ethanediamine) or DME (DME=1,2-dimethoxyethane) are added to mEthyllithium, tetrameric units are linked to form polymeric arrays that suffer from reduced reactivity and/or solubility. In this paper we present two different approaches to tune mEthyllithium aggregation. In [[(MeLi)4(dem)1,5)infinity] (1; DEM = EtOCH2OEt, diethoxymethane) a polymeric architecture is maintained that forms microporous soluble aggregates as a result of the rigid bite of the methylene-bridged bidentate donor base DEM. Wide channels of 720 pm in diameter in the structure maintain full solubility as they are coated with lipophilic ethyl groups and filled with solvent. In compound 1 the long-range Li3CH3...Li interactions found in solid [[(MeLi)4]infinity] are maintained. A different approach was successful in the disassembly of the tetrameric architecture of [((MeLi)4]infinity]. In the reaction of dilithium triazasulfite both the parent [(MeLi)4] tetramer and the [[Li2[(NtBu)3S]]2] dimer disintegrate and recombine to give an MeLi monomer stabilized in the adduct complex [(thf)3Li3Me-[(NtBu)3S]] (2). One side of the Li3 triangle, often found in organolithium chemistry, is shielded by the tripodal triazasulfite, while the other face is mu3-capped by the methanide anion. This Li3 structural motif is also present in organolithium tetramers and hexamers. All single-crystal structures have been confirmed through solid-state NMR experiments to be the same as in the bulk powder material.
Bernhard Walfort - One of the best experts on this subject based on the ideXlab platform.
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meli 4 dem 1 5 and thf 3li3me ntbu 3s how to reduce aggregation of parent mEthyllithium
Chemistry: A European Journal, 2001Co-Authors: Bernhard Walfort, Lutz Lameyer, Regine Herbstirmer, Wilfried Weiss, Rüdiger Bertermann, Joao Rocha, Dietmar StalkeAbstract:: Organolithium compounds play the leading role among the organometallic reagents in synthesis and in industrial processes. Up to date industrial application of mEthyllithium is limited because it is only soluble in diethyl ether, which amplifies various hazards in large-scale processes. However, most reactions require polar solvents like diethyl ether or THF to disassemble parent organolithium oligomers. If classical bidentate donor solvents like TMEDA (TMEDA= N,N,N',N'tetramethyl-1,2-ethanediamine) or DME (DME=1,2-dimethoxyethane) are added to mEthyllithium, tetrameric units are linked to form polymeric arrays that suffer from reduced reactivity and/or solubility. In this paper we present two different approaches to tune mEthyllithium aggregation. In [[(MeLi)4(dem)1,5)infinity] (1; DEM = EtOCH2OEt, diethoxymethane) a polymeric architecture is maintained that forms microporous soluble aggregates as a result of the rigid bite of the methylene-bridged bidentate donor base DEM. Wide channels of 720 pm in diameter in the structure maintain full solubility as they are coated with lipophilic ethyl groups and filled with solvent. In compound 1 the long-range Li3CH3...Li interactions found in solid [[(MeLi)4]infinity] are maintained. A different approach was successful in the disassembly of the tetrameric architecture of [((MeLi)4]infinity]. In the reaction of dilithium triazasulfite both the parent [(MeLi)4] tetramer and the [[Li2[(NtBu)3S]]2] dimer disintegrate and recombine to give an MeLi monomer stabilized in the adduct complex [(thf)3Li3Me-[(NtBu)3S]] (2). One side of the Li3 triangle, often found in organolithium chemistry, is shielded by the tripodal triazasulfite, while the other face is mu3-capped by the methanide anion. This Li3 structural motif is also present in organolithium tetramers and hexamers. All single-crystal structures have been confirmed through solid-state NMR experiments to be the same as in the bulk powder material.
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meli 4 dem 1 5 and thf 3li3me ntbu 3s how to reduce aggregation of parent mEthyllithium
Chemistry: A European Journal, 2001Co-Authors: Bernhard Walfort, Lutz Lameyer, Regine Herbstirmer, Wilfried Weiss, Rüdiger Bertermann, Joao Rocha, Dietmar StalkeAbstract:: Organolithium compounds play the leading role among the organometallic reagents in synthesis and in industrial processes. Up to date industrial application of mEthyllithium is limited because it is only soluble in diethyl ether, which amplifies various hazards in large-scale processes. However, most reactions require polar solvents like diethyl ether or THF to disassemble parent organolithium oligomers. If classical bidentate donor solvents like TMEDA (TMEDA= N,N,N',N'tetramethyl-1,2-ethanediamine) or DME (DME=1,2-dimethoxyethane) are added to mEthyllithium, tetrameric units are linked to form polymeric arrays that suffer from reduced reactivity and/or solubility. In this paper we present two different approaches to tune mEthyllithium aggregation. In [[(MeLi)4(dem)1,5)infinity] (1; DEM = EtOCH2OEt, diethoxymethane) a polymeric architecture is maintained that forms microporous soluble aggregates as a result of the rigid bite of the methylene-bridged bidentate donor base DEM. Wide channels of 720 pm in diameter in the structure maintain full solubility as they are coated with lipophilic ethyl groups and filled with solvent. In compound 1 the long-range Li3CH3...Li interactions found in solid [[(MeLi)4]infinity] are maintained. A different approach was successful in the disassembly of the tetrameric architecture of [((MeLi)4]infinity]. In the reaction of dilithium triazasulfite both the parent [(MeLi)4] tetramer and the [[Li2[(NtBu)3S]]2] dimer disintegrate and recombine to give an MeLi monomer stabilized in the adduct complex [(thf)3Li3Me-[(NtBu)3S]] (2). One side of the Li3 triangle, often found in organolithium chemistry, is shielded by the tripodal triazasulfite, while the other face is mu3-capped by the methanide anion. This Li3 structural motif is also present in organolithium tetramers and hexamers. All single-crystal structures have been confirmed through solid-state NMR experiments to be the same as in the bulk powder material.
Liangfu Tang - One of the best experts on this subject based on the ideXlab platform.
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reactivity of bis 3 5 dimethylpyrazol 1 yl mEthyllithium with s or cs2 followed by reaction with fe3 co 12 and ar3sncl or rx unexpected formation of 3 5 dimethylpyrazol 1 yl dithioformate derivatives
Organometallics, 2012Co-Authors: Xiaoyan Zhang, Haibin Song, Liangfu TangAbstract:Reaction of bis(3,5-dimethylpyrazol-1-yl)mEthyllithium with sulfur at −70 °C, followed by reaction with Fe3(CO)12 and triaryltin chlorides, yielded trinuclear butterfly cluster complexes. When the triaryltin chlorides were replaced by organic halides, unexpected (3,5-dimethylpyrazol-1-yl)dithioformate derivatives were obtained. In addition, treatment of bis(3,5-dimethylpyrazol-1-yl)methane with n-BuLi at 0 °C resulted in partial decomposition to yield a carbene intermediate and a 3,5-dimethylpyrazolate anion. The carbene intermediate readily dimerized, and reaction of the anion with carbon disulfide, and subsequently with Fe3(CO)12 and organic halides, also gave the dithioformate derivatives.
Nikolay S. Zefirov - One of the best experts on this subject based on the ideXlab platform.
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gem bromochlorospiropentane reactivity toward mEthyllithium an unusual carbenoid rearrangement
Tetrahedron, 2010Co-Authors: Kseniya N Sedenkova, Yuri K Grishin, Elena B Averina, Tamara S Kuznetzova, Nikolay S. ZefirovAbstract:A skeletal carbenoid rearrangement of the gem-bromochlorospiropentanes in the presence of mEthyllithium has been studied. The synthetic and mechanistic aspects of this rearrangement as well as the influence of the halogen atom nature on the reaction pathway are discussed.
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unusual methylation reaction of gem bromofluorospiropentanes with mEthyllithium
Tetrahedron, 2009Co-Authors: Elena B Averina, Kseniya N Sedenkova, Yuri K Grishin, T S Kuznetsova, Ilya S Borisov, Nikolay S. ZefirovAbstract:A series of novel gem-bromofluorospiropentanes were synthesized and investigated in the reaction with mEthyllithium. Either substitution of the fluorine atom for a methyl group or rearrangement into methylated cyclobutene derivatives occurred under these conditions.
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reaction of polyspirocyclic internal gem dibromocyclopropanes with mEthyllithium an unusual carbenoid rearrangement
Arkivoc, 2008Co-Authors: Elena B Averina, Kseniya N Sedenkova, Yuri K Grishin, Tamara S Kuznetzova, Nikolay S. ZefirovAbstract:A skeletal rearrangement of a series of polyspiro internal gem dibromocyclopropanes in the presence of mEthyllithium reagents was studied. The rearranged products of two types were obtained: substituted bromocyclobutenes (type B) and C-H insertion products (type K) resulting from the reaction of the carbenoid intermediate H with the ether solvent. The mechanism of the carbenoid rearrangement is discussed.
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reaction of 2 2 dibromotricyclo 7 1 01 9 01 3 decane with mEthyllithium synthesis of bicyclo 7 1 0 decadiene 1 2 and dibromotriangulane rearrangement
Mendeleev Communications, 1999Co-Authors: Elena B Averina, Yuri K Grishin, T S Kuznetsova, Alexey N Zefirov, Alexey E Koposov, Nikolay S. ZefirovAbstract:Reaction of 2,2-dibromotricyclo[7.1.01,9.01,3]decane with mEthyllithium gives strained cyclic allene 1 containing an ethenylidene-cyclopropane unit in a nine-membered ring and dimer 6 resulting from a dibromotriangulane rearrangement.
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unusual rearrangement of triangulane gem dibromides in the presence of mEthyllithium
Tetrahedron, 1992Co-Authors: K A Lukin, Nikolay S. Zefirov, Dimitrii S. Yufit, Yuri T StruchkovAbstract:Abstract Triangulane gem-dibromides in the presence of mEthyllithium undergo rearrangement of dibromospiropentyl fragment into 1-bromomethyl-2-bromocyclobutenyl one.
Michael L Mckee - One of the best experts on this subject based on the ideXlab platform.
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density functional calculations of mEthyllithium t butyllithium and phenyllithium oligomers effect of hyperconjugation on conformation
Journal of Physical Chemistry A, 2001Co-Authors: Ohyun Kwon, Michael L MckeeAbstract:Oligomers of mEthyllithium and tert-butyllithium (RnLin, n = 1−4; R = Me, t-Bu) as well as phenyllithium (PhnLin, n = 1,4) have been studied by using density functional theory (DFT). Possible conformers of mEthyllithium and tert-butyllithium oligomers were optimized at the B3LYP/6-31+G* level, and relative energies were evaluated at the B3LYP/6-311+G(2d,p)+ZPC//B3LYP/6-31+G* level. Optimized geometric parameters of MeLi and t-BuLi tetramers are in good agreement with available experimental and previous computational results. Atomic charges from natural population analysis (NPA) indicate that Li−C bonds show dominant ionic character for methyl, tert-butyl, and phenyllithium oligomers. Comparison of atomic charges among the oligomers indicates that lithium charges are almost independent of the size of the oligomer or the identity of the ligand. NBO second-order perturbation energy analyses for the Td geometries of mEthyllithium and tert-butyllithium tetramers indicate that the hyperconjugative interaction (...
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density functional calculations of mEthyllithium t butyllithium and phenyllithium oligomers effect of hyperconjugation on conformation
Journal of Physical Chemistry A, 2001Co-Authors: Ohyun Kwon, Fatma Sevin And, Michael L MckeeAbstract:Oligomers of mEthyllithium and tert-butyllithium (RnLin, n = 1−4; R = Me, t-Bu) as well as phenyllithium (PhnLin, n = 1,4) have been studied by using density functional theory (DFT). Possible confo...