Unstable halogenated organolithium compounds

Conclusions When the decomposition of o-fluorophenyllithium tetrahydrofuranate was carried out in the presence of furan, it was shown that 50% of the dehydrobenzene formed has kinetic freedom.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1089–1091, May, 1978.For communication 4, see [1].     

Reactions of haloaryloxysilanes with organolithium compounds

Conclusions The 1,3-anionic rearrangement of aryloxysilanes is an intramolecular process that does not depend on the nature of the migrating organosilyl group but is controlled by the reactivities of the labile halogen of the aryloxysilane and of the organolithium compound in the halogen-lithium exchange reaction, which generates the silyloxyarenide ion.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 890–893, April, 1978.     

Reaction of deoxyvasicinone with organolithium compounds

4-Butyl-4-hydroxydeoxypeganine was prepared by lithiation of deoxyvasicinone. Deoxypeganine and 1,2-dihydrodeoxypeganine were produced by reduction of deoxyvasicinone with lithium aluminum hydride.     

Polymerization of dienes using organolithium compounds

In this paper an interpretation is given of the polymerization mechanism of diene and styrene monomers with organolithium compounds (LOC).An attempt will be made to correlate the nature of living chains to the structure of the polymer formed.     

Unstable halogen-containing organolithium compounds. 7. Thermodynamic calculations of the decomposition mechanism of halogen-containing organolithium compounds

Conclusions The influence of the halogen on the strength of the adjacent C-Li bond has been evaluated on the basis of thermodynamic and quantum-chemical calculations, and it has been shown that monomolecular decomposition is preferable for LiCHCl₂, LiCCl₃, LiCF₃, and o-FC₆H₄Li under the conditions of the experiment, while such decomposition is impossible for LiCH₂Cl.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2183–2186, October, 1979.     

Functionalization of polymeric organolithium compounds with formaldehyde

Functionalizations of poly(styryl)lithium (PSLi), poly(butadienyl)lithium (PBDLi), and poly(isoprenyl)lithium (PILi) with formaldehyde were investigated in benzene solutions at room temperature. Dimer and unfunctionalized products, in addition to the expected products, were found in the PSLi functionalization with formaldehyde. The byproducts were analyzed by ¹H NMR, ¹³C NMR, size exclusion chromatography (SEC), and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) and showed evidence for Cannizzaro reactions and electron‐transfer reactions. A molecular weight dependence of the dimer formation was found for PSLi functionalizations for number‐average molecular weights of less than 20,000; the dimer formation decreased as the molecular weight increased. Changing the reaction conditions did not eliminate dimer formation in the PSLi functionalization. The reactions of PBDLi and PILi with formaldehyde effected quantitative functionalizations, as determined by SEC, ¹H NMR, ¹³C NMR, MALDI‐TOF MS, quantitative column chromatography, and end‐group titration. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2435–2453, 2003     

Chemoselective acylation of some oxidofunctionalised organolithium compounds

Once oxidofunctionalised organolithium compounds 1 (easily prepared by reductive ring opening of isochroman and phthalan by DTBB-catalysed lithiation) were transmetallated with ZnBr₂/CuCN·2LiCl and reacted successively with a carboxylic acid anhydride and an acyl chloride in THF at 0°C, the corresponding differently acylated compounds 4 were obtained after hydrolysis with water. The anhydride performed the O-acylation exclusively and the acyl chloride carried out the C-acylation.     

Reaction of 1,1-difluorocyclopropanes with organolithium compounds

Substituted 1,1-difluorocyclopropanes react with organolithium reagents to provide either cyclopropenes or mono-substituted acetylenes depending upon the substitution patterns.     

Functionalization of polymeric organolithium compounds. Oxidation

The oxidation of poly(styryl)lithium with molecular oxygen was investigated in the solid state (with and without N,N,N′, N′-tetramethylethylenediamine) in benzene (with and without N,N,N′, N′-tetramethylethylenediamine) and in benzene/tetrahydrofuran (THF) solutions. The oxidation products included the corresponding polystyrene dimer [(PS)₂], the dimeric poly(styrene) peroxide (PSO₂PS), poly(styrene) hydroperoxide (PSO₂H), and the hydroxyl-terminated polymer (PSOH). The hithertofore unreported macroperoxide (PSO₂PS) accounts for approximately 50% of the dimeric product obtained from poly(styryl)lithium oxidations in the presence of Lewis bases. The total amount of peroxide products was determined by iodometric titration in the presence of a phase-transfer catalyst, dicyclohexyl-18-crown-6. On the basis of the effect of polar additives on the amount of dimeric products, it is concluded that dimer formation in the air termination of polymeric organolithium compounds results from oxidation and not carbonation reactions.     

Structural modification of steroids through functionalised organolithium compounds

The reaction of the epoxysteroids 1 and 4, derived from estrone and cholestanone, respectively, with an excess of lithium and a catalytic amount of DTBB (7 mol%) in THF at −78°C, leads to the formation of the corresponding β-oxido-functionalised organolithium intermediates 2 and 5, respectively, which, by reaction with different electrophiles [H₂O, D₂O, PhCHO, Me₂CO, Et₂CO, (CH₂)₅CO, CO₂] at −78°C to room temperature, afford, after hydrolysis with water, enantiomerically pure compounds 3 and 6, respectively. The stereochemistry of all these compounds was unambiguously determined by correlation with X-ray data for compound 3d and by comparison with the known compound 6a.