15082-42-5Relevant articles and documents
Developing Lithium Chemistry of 1,2-Dihydropyridines: From Kinetic Intermediates to Isolable Characterized Compounds
Armstrong, David R.,Harris, Catriona M. M.,Kennedy, Alan R.,Liggat, John J.,McLellan, Ross,Mulvey, Robert E.,Urquhart, Matthew D. T.,Robertson, Stuart D.
, p. 14410 - 14420 (2015)
Generally considered kinetic intermediates in addition reactions of alkyllithiums to pyridine1-lithio-2-alkyl-1,2-dihydropyridines have been rarely isolated or characterized. This study develops their "isolated" chemistry. By a unique stoichiometric (that is1:1alkyllithium/pyridine ratios) synthetic approach using tridentate donors we show it is possible to stabilize and hence crystallize monomeric complexes where alkyl is tert-butyl. Theoretical calculations probing the donor-free parent tert-butyl species reveal 12 energetically similar stereoisomers in two distinct cyclotrimeric (LiN)3 conformations. NMR spectroscopy studies (including DOSY spectra) and thermal volatility analysis compare new sec-butyl and iso-butyl isomers showing the former is a hexane soluble efficient hydrolithiation agent converting benzophenone to lithium diphenylmethoxide. Emphasizing the criticalness of stoichiometryreaction of nBuLi/Me6TREN with two equivalents of pyridine results in non-alkylated 1-lithio-1,4-dihydropyridine·Me6TREN and 2-n-butylpyridineimplying mechanistically the kinetic 1,2-n-butyl intermediate hydrolithiates the second pyridine.
Structural Characterization of Tridentate N-Heterocyclic Carbene Titanium(IV) Benzyloxide, Silyloxide, Acetate, and Azide Complexes and Assessment of Their Efficacies for Catalyzing the Copolymerization of Cyclohexene Oxide with CO2
Quadri, Coralie C.,Lalrempuia, Ralte,Hessevik, Julie,T?rnroos, Karl W.,Le Roux, Erwan
, p. 4477 - 4489 (2017)
The reactivity of tridentate bis-aryloxy N-heterocyclic carbene (NHC) titanium complexes ([κ3-O,C,O]-NHC)Ti(X1)(X2) (X1 = X2 = Cl (1); X1 = X2 = OiPr (2)) via salt metathesis (wi
Experimental and computational studies of borohydride catalyzed hydrosilylation of a variety of C=O and C=N functionalities including esters, amides and heteroarenes
Manas, Michael G.,Sharninghausen, Liam S.,Balcells, David,Crabtree, Robert H.
supporting information, p. 1694 - 1700 (2014/05/06)
Sodium borohydride and a series of related borohydrides catalyze a transition metal-free hydrosilylation of a variety of C=O and C=N functionalities under mild conditions. Importantly, many of these reactions are possible using the cheap and environmentally benign hydrosilane polymethylhydrosiloxane. A mechanism is proposed based on experimental and computational results.
Lithium alkoxide-promoted michael reaction between silyl enolates and α,β-unsaturated carbonyl compounds
Mukaiyama, Teruaki,Tozawa, Takashi,Fujisawa, Hidehiko
, p. 1410 - 1411 (2007/10/03)
Michael reaction between silyl enolates and α,β-unsaturated carbonyl compounds by using a catalytic amount of Lewis base such as lithium alkoxide in DMF proceeds smoothly to afford the corresponding Michael-adducts in good yields with moderate to high diastereoselectivities. This reaction can be reasonably explained by considering an alkoxide anion-initiated autocatalytic process.
Process for preparing acetoxyazetidinone derivative and intermediate thereof
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, (2008/06/13)
An N-?2-(1-hydroxyethyl)-3-oxopropyl!amine compound of the formula ?III!: STR1 wherein Ring B represents a benzene ring which may be substituted; W represents oxygen atom or sulfur atom; Y represents oxygen atom, sulfur atom or N R0, R0 represents hydrogen atom or a substituent; Z represents a substituted methylene group which contains at least one chiral center; R5 represents an aralkyloxycarbonyl group or an alkoxycarbonyl group; R6 represents hydrogen atom, an aralkyl group, an acyloxy group, a tri-substituted silyloxy group or an alkoxy group; or both of R5 and R6 bond at their termini and combine with the adjacent nitrogen atom to form phthalimido group, and a process thereof are disclosed. Said compound ?III! is useful as a starting compound of β-lactam antibacterial agents.
Proton affinities and aggregation states of lithium alkoxides, phenolates, enolates, β-dicarbonyl enolates, carboxylates, and amidates in tetrahydrofuran
Arnett, Edward M.,Moe, Kevin D.
, p. 7288 - 7293 (2007/10/02)
The proton affinities of the title compounds are represented by their heats of deprotonation, ΔHdep, through reactions with lithium bis(trimethylsilyl)amide, LiHMDS, in tetrahydrofuran at 25°C. Aggregation numbers of the parent acid and of its lithium salt at a concentration of 0.10 M were obtained by vapor-pressure osmometry at 37°C. Lithium phenolates were also studied by conductivity at 25°C. ΔHdeps for 27 oxygen, nitrogen, and carbon acids of varied types correlate fairly well (R = 0.95) with their published pKas in dimethyl sulfoxide although their degrees of aggregation in THF vary from one to over seven. In some cases, the ΔHdep of an acid is strongly dependent on the concentration ratio of LiHMDS to that of the acid's lithium salt at the time of measurement. Aggregation numbers determined by VPO in this report agree with available published values obtained by previous workers using several techniques. There is no obvious relationship between the aggregation number of the lithium salt and the basicity of the corresponding anion as represented by ΔHdep. This observation along with independent evidence for equilibria between monomers, dimers, tetramers, etc. for a number of compounds indicate that there are only small differences between the relative stabilities of different aggregation states. Conductance data for lithium p-nitrophenolate were treated by Wooster analysis, the results of which suggest equilibria between ion triplets, ion pairs, and free ions in THF. The conductance of LiHMDS in this solvent is surprisingly high, and this property was used to demonstrate an interaction between LiHMDS and lithium o-tert-butylphenolate.
