Equivalents Of Butyllithium Research Articles

The One-Pot Conversion of (Trichlorovinyl)amines into Ethynylenediamines

Treatment of N, N-disubstituted (trichlorovinyl)amines 1 with an equimolar mixture of butyllithium and lithium diorganoamides, prepared from the corresponding secondary amine and two equivalents of butyllithium, furnishes symmetrically and unsymmetrically substituted ethynylenediamines 4 (1,2-ethynediamines).

Azoles. Part 5. Metal-halogen exchange reactions of polybromoimidazoles

1,2-Dilithiated imidazoles were prepared by treating 2-bromo-4,5-dichloro- and 2,4,5-tribromoimidazole with 2 equivalents of butyl-lithium and trapped with various electrophiles to give moderate yields of the 2-substituted 4,5-dihalogeno compounds (4)–(10). The 4,5-dibromoimidazole (4), prepared in this way, was converted into the 1-protected derivatives (18)–(22)(protecting group = CH2CH2SO2Ph, CH2CO2Et, CPh3, SO2Ph, SO2C6H4Me-4). 4-Bromo-5-chloro-1-tritylimidazole was prepared similarly. Successive treatment of 4,5-dibromoimidazole with 2 equivalents of butyl-lithium, benzophenone, and acid gave a low yield of 4(5)-bromoimidazol-5(4)-yldiphenylmethanol (11). Whereas 1-protected 2,4,5-tribromoimidazoles [P = CH2OMe, CH2OEt, CH2Ph, CH2C6H4OMe-4, CH2C6H3(OMe)2-3,4] reacted at both the 2- and 5-bromine atoms with 1 equivalent of butyl-lithium, they reacted with 1 equivalent of other organometallic reagents (EtMgBr, MeLi, s-BuLi, PhLi) regioselectively at the 2-position and the intermediate organometallic compounds were either hydrolysed or quenched with benzophenone, to give the corresponding 1-protected 4,5-dibromoimidazoles (13)–(17) and compound, (25), respectively, in good yields. Compounds (13)–(17) were treated with a further equivalent of butyl-lithium and the resulting imidazol-5-yl-lithium derivatives were either quenched with an electrophile or hydrolysed with water; e.g. 1-benzyl-4-bromoimidazol-5-yl-lithium was treated with dimethylformamide (DMF), carbon dioxide, methyl chloroformate, and elemental sulphur to give compounds (33)–(36), respectively. Other 1-protected 4-bromoimidazole-5-carbaldehydes, (31), (32), and (37)–(40) were prepared similarly from the corresponding 4,5-dibromoimidazole.

An improved procedure for the generation and selective trapping of 2,4′-dilithiophenylethyne

2,4′-Dilithiophenylethyne, prepared by treatment of 4-bromophenylethyne with two equivalents of butyllithium, reacts selectively with electrophilic reagents at the 4′-position provided the correct temperature and solvent combination are employed. The successive addition of two different electrophiles gives the 2,4′-dialkylated product in a regioselective manner.

Stereospecific Desulfinylation of α,β-Epoxy Sulfoxides with Butyllithium. A New Synthesis of Epoxides and Allylic Alcohols from Carbonyl Compounds

Abstract Desulfinylation of α,β-epoxy sulfoxides, easily prepared from carbonyl compounds and 1-chloroalkyl phenyl sulfoxide, with 1 equivalent of butyllithium at low temperature gave epoxides in good yields. The similar α,β-epoxy sulfoxides having an arylmethyl group at the α-position gave 3-aryl-allylic alcohols upon treatment with excess butyllithium at −70 °C. These reactions offer a simple and useful approach to the synthesis of epoxides and 3-aryl-allylic alcohols from a carbonyl compound.

ChemInform Abstract: Dimetallation of Phenylacetylene. Synthesis of ortho‐Substituted Derivatives of Phenylacetylene, Benzo[b]selenophene and Benzo[b]tellurophene.

AbstractDie Reaktion der dimetallierten Phenylacetylene (I) [bei direkter Lithiierung von (IIa) zu (Ic) entstehen Regioisomeren‐Gemische] mit den Elektrophilen (III)‐(VI) führt regioselektiv zu den ortho‐substituierten Derivaten (IIb)‐(IIe); die Umsetzungen mit (VII) und (VIII) hingegen ergeben z.T. [bei (Ib) ausschließlich] auch die am Alkin substituierten Produkte (IX) [(IIg) ist nur über die disilylierte Verbindung zugänglich].

Dimetallation of phenylacetylene. Synthesis of ortho‐substituted derivatives of phenylacetylene, benzo[b]selenophene and benzo[b]tellurophene

AbstractPhenylacetylene can be dimetallated in two ways. o‐K‐C6H4‐C  C ‐ Li is formed by treating phenylacetylene at −70°C with two equivalents of butyllithium and one equivalent of potassium tert‐butoxide in a mixture of tetrahydrofuran and hexane. The dimetallation with BuLi‐N,N,N′, N′‐tetramethylethanediamine (TMEDA) affords a mixture of about 15% (m + p)‐Li‐C6H4‐C  C Li and 85% o‐Li‐C6H4‐C  C‐Li. Ortho‐K‐C6H4‐C  C‐Li can be transformed into the dilithio or di‐Grignard derivatives by addition of anhydrous lithium bromide or magnesium bromide etherate. Reaction of the dilithio derivative with elemental selenium and tellurium, followed by successive addition of tert‐butyl alcohol and hexamethylphosphoric triamde (HMPT), gives benzo[b]selenophene and benzo[b]tellurophene in good yields.Regiospecific functionalization of the nucleus via dimetal derivatives succeeds in the case of alkylation, halogenation, sulfenylation and acylation (with dimethylformamide and dimethylacetamide). Trimethylchlorosilane, chloromethyl methyl ether, aldehydes and ketones do not however react regiospecifically.

Synthese von ‘Push‐Pull’‐Diacetylenen

Synthesis of ‘Push‐Pull’ DiacetylenesThe first synthesis of push‐pull diacetylenes of type 1 is described. Reaction of perchlorobutenyne (8) with two equivalents of dialkylamine, followed by dechlorination using two equivalents of butyllithium gives lithio‐dialkylamino‐diynes 7. Final acylation of these intermediates leads to push‐pull diacetylenes 1b–1e in good yields. The method allows the introduction of both push and pull substituents in a simple one‐pot‐procedure. In addition, 1a is prepared by hydroxymethylation of lithio‐morpholino‐diyne 7c, followed by oxidation with manganese dioxide in acetone.

The reaction of chloromagnesium bis(2,3,5,6-tetrachlorophenyl)copper with butyllithium

Chloromagnesium bis(2,3,5,6-tetrachlorophenyl)copper, prepared from two equivalents of 2,3,5,6-tetrachlorophenylmagnesium chloride and one equivalent of copper(I) chloride inTHF, reacts with one equivalent of butyllithium at −78°C to give, subsequent to derivatisation with chlorotrimethylsilane and then with acetyl chloride, (1-acetyl-2,3,5,6-tetrachlorophenyl)trimethylsilane (20%), 1-(trimethylsilyl)-2,3,5,6-tetrachlorobenzene (17%) and 1-acetyl-2,3,5,6-tetrachlorobenzene (34%) along with some trace products. The formation of these products is explained on the basis of the intermediate formation of chloromagnesium bis(1-lithio-2,3,5,6-tetrachlorophenyl)copper, a functionalised cuprate reagent.

The reaction of 2,3,4-trichlorothiophene with alkyllithium reagents

2,3,4-Trichlorothiophene undergoes metal-hydrogen exchange with one equivalent of butyllithium inTHF at −78°C to give trichloro-2-thienyllithium in 91% yield. No metal-halogen exchange is observed to have taken place. Witht-butyllithium under similar conditions, however, the metalhalogen exchange reaction occurs but only to the extent of 8%; the main reaction remains to be the metal-hydrogen exchange. 2,3,4-Trichlorothiophene reacts with two equivalents of butyllithium in ether at −5°C to give 3,4-dichloro-2,5-dilithiothiophene in 96% yield.

Preparation of 1-dialkylamino-1,2,3-trienes, a novel type of cumulenes

Solutions of α-lithiated cumulenic amines are produced upon treatment of l-dialkylamino-4-methoxy-4-methyl-2-pentynes with two equivalents of butyllithium. Subsequent protonation with t-butyl alcohol gives the corresponding cumulenic amines, while treatment with trimethylchlorosilane gives the α-trimethylsilylated derivatives.

ChemInform Abstract: A NEW REACTION OF 1‐BROMOALK‐1‐YNES, SYNTHESIS OF 3‐ALKYLALK‐1‐YNES FROM TERMINAL ACETYLENES

AbstractDie Umsetzung der Bromalkine (I) mit n‐Butyllithium in Hexan ergibt die n‐Butylalkine (II).

Notizen: Umlagerungen metallierter, organosubstituierter Harnstoffe, II / Rearrangements of Metallated Organosubstituted Ureas, II

By the reaction of two equivalents of butyllithium with N-benzyl-N,N′-diorganylureas, no dimetallated ureas were recovered; rather intensive-coloured solutions were formed, with subsequent identification of N, α-diorganylbenzylamnines and lithiumcyanate.

A new reaction of 1-bromoalk-1-ynes; synthesis of 3-alkylalk-1-ynes from terminal acetylenes

The reaction of 1-bromoalk-1-ynes with two equivalents of butyl-lithium in hexane gives 3-butylalk-1-ynes; the reactive intermediate is a dilithioalkyne which can also be directly prepared from terminal acetylenes, and selective reaction with alkyl halides in hexane occurs at the propargylic site to provide a general synthesis of 3-alkylalk-1-ynes.

Existence d'un dianion allénique derivant du méthoxy-3 phényl-1 propyne-1 synthèse de derivés alléniques éthers fonctionnels et de composés carbonylés α,β éthylèniques

Abstract 3-Methoxy-1-phenyl-1-propyne treated at −75° by two equivalents of butyl-lithium in ether gives a dianion whose structure is allenic. This dianion offers various possibilities of selective mono and bialkylation rections with excellent yields. Hydrolysis of allenic ether derivatives liberates α-ethylenic aldehydes or ketones.

A general method for the preparation of cumulenic ethers and thioethers

AbstractSolutions of lithiated cumulenic ethers and bis‐ethers R2CHCCC(Li)OR3 and R1OCHCCC(Li)OR3 can be obtained by treatment of the compounds R1OCH(R)2)CCCH2OR3 and R1OCH2CCCH(OR3)2 respectively with 2 equivalents of butyllithium in ether. Reaction of these solutions with H2O, D2O, methyl iodide, α‐chloro‐ethers or ketones gives the cumulenic compounds or their derivatives in good yields.Solutions of lithiated cumulenic thioethers R2CHCCC(Li)SR3 are obtained in an analogous way, but hydrolysis affords the isomeric enynic thioethers R2CHCHCCSR3 in addition to the expected cumulenic thioethers R2CHCCCHSR3. Elimination of R1OH from R1OC(R2)2CCCH(SR3)2 with 1 equivalent of C4H9Li leads to the cumulenic dithioacetals (R2)2CCCC(SR3)2.