Lambert Brandsma

Copper(I) halide catalysed synthesis of alkyl aryl and alkyl heteroaryl ethers

Abstract A number of alkyl aryl and alkyl heteroaryl ethers have been prepared from (hetero) aryl halides (mainly bromides) and sodium alkoxides, using copper(I)bromide as a catalyst. The influence of the main solvent, the halogen atom, reaction temperature and the presence of oxygen upon the rate and selectivity has been studied. Furthermore the decomposition of the catalyst and the reduction of the aryl halide are studied.

NUCLEOPHILIC ADDITION OF PHOSPHINE TO ARYL- AND HETARYLETHENES : A CONVENIENT SYNTHESIS OF BIS(2-ARYLALKYL)- AND BIS(2-HETARALKYL)PHOSPHINES

Abstract A number of secondary phosphines [RCH(R′)CH 2 ] 2 PH (R = aryl or hetaryl, R′ = H or Me) have been obtained in good yields by introducing phosphine at normal pressure into a mixture of the alkenes R(R′)CCH 2 , potassium hydroxide and dimethylsulfoxide.

Transition metal catalysed cross-coupling between benzylic halides and aryl nucleophiles. Synthesis of some toxicologically interesting tetrachlorobenzyltoluenes.

Abstract The aryl-benzyl cross-coupling in the presence of copper-, nickel- and palladium-catalysts has been investigated with a number of chlorine- and methyl-substituted arylmetal compounds ArM (M=MgBr, ZnCl) and (substituted) benzylic halides ArCH2X. The results have been applied in the selective synthesis of some toxicologically interesting tetrachlorobenzyltoluenes.

Application of copper catalysis in a one-pot procedure for 1-alkyl-3-methoxy-2-methylthiopyrroles starting from methoxyallene and alkyl isothiocyanates

Abstract 1-Alkyl-3-methoxy-2-methylthiopyrroles are obtained with high purities and in high yields by Cu(I)halide-catalyzed cyclization of the products from addition of 1-lithiomethoxyallene to alkyl isothiocyanates and subsequent methylation.

Synthesis of 2,5-bis(N,N-dialkylamino)thiophenes or 1-alkyl-2-N,N-dialkylamino-5-methylthiopyrroles from propargylic amines and isothiocyanates

Abstract Reaction of lithiated propargylic amines with isothiocyanates, followed by addition of t -BuOK, t -BuOH and methyl iodide gives either 2,5-bis( N,N -dialkylamino)thiophenes or 1-alkyl-2- N,N -dialkylamino-5-methylthiopyrroles depending on the temperature during the treatment with the base.

Nickel-Catalyzed Cyanation of 2- and 3- Bromothiophene

Abstract Trans-chloro-(2-naphthyl)-bis-(triphenylphosphine)nickel has been used to catalyze the conversion of 2-and 3-bromothiophene with alkali cyanide into the corresponding nitriles. A modified procedure for preparing the catalyst is described.

Synthesis of 2,3-dihydropyridines, cyclobutanopyrrolines and quinolines from lithiated allenes and isothiocyanates

Abstract The products obtained by S -alkylation of the adducts from lithiated allenes and alkyl or aryl isothiocyanates undergo thermal rearrangements with ultimate formation of derivatives of 2,3-dihydropyridine, cyclobutanopyrroline and quinoline, depending on the structure of the isothiocyanate. In some reactions azatrienes with a fully conjugated system can be isolated.

Efficient Procedures for the Cu(I)-Catalyzed Methoxylation of 2-and 3-Bromothiophene

Abstract Substitution of halogens in aromatic and heteroaromatic compounds by alkoxide or aryloxy groups is catalyzed by copper, and its salts.1–4 In most cases complete conversion requires prolonged heating at elevated temperatures.

The structure of 2-(diphenylphosphino)phenyllithium: the significance of PLi bonding

Abstract The solid state structure of 2-(diphenylphosphino)phenyllithium·Et 2 O has been determined by a single crystal X-ray diffraction study. The crystal consists of dimeric aggregates in which the Li atoms are solvated by an additional diethyl ether molecule. The compound retains the dimeric structure in an apolar solvent (toluene) but in THF it exists in monomeric form. Ab initio calculations indicate a small but significant influence of PLi interaction on the stability and structure of P-containing organolithium compounds.

The molecular structure of 1-lithio-2-methoxybenzene in the solid state and in solution

Abstract The X-ray structure of 1-lithio-2-methoxybenzene (2-methoxyphenyllithium) has been determined at 298 K by single crystal X-ray techniques. The compound crystallizes in the triclinic system with spacegroup P 1¯. Cell dimensions: a 8.889(2),b 11.710(5),c 12.941(3)A, α 80.47(3), β 84.22(2), γ 82.37(3)°. The structure has been refined toR(F) = 0.069 for 1300 unique observed reflections withI ≥ 2.5σ(I). Each unit-cell contains two centrosymmetrically related tetrameric units which show Li ⋯ HC interactions with each other. Its structure in solution has been determined by NMR spectroscopy and association measurements. The influence of various Lewis bases on the solution structure has been studied.