Carbonyl allylations by allylic chlorides utilizing a reduction of tin(IV) iodide to triiodostannate(II) species with iodide sources

Carbonyl allylations by allylic chlorides either with tin(IV) iodide and tetrabutylammonium iodide (TBAI) in dichloromethane or with tin(IV) iodide and sodium iodide in 1,3-dimethylimidazolidin-2-one at room temperature produced the corresponding homoallylic alcohols. The carbonyl allylations probably proceeded via the reduction of tin(IV) iodide to triiodostannate(II) species with iodide sources such as TBAI and NaI, which led to the construction of a tin(IV)-catalytic cycle based on regeneration of tin(IV) iodide via the transmetalation of homoallyloxytriiodotin to homoallyloxytrimethylsilane with iodotrimethylsilane.     

Preparation of iron carbonyl complexes of germanium(II) and tin(II) each with a terminal fluorine atom

The reaction of β-diketiminate substituted germanium(II) and tin(II) fluorides (LGeF (1) and LSnF (2)) (L = CH{(CMe)₂(2,6-iPr₂C₆H₃N)₂}) with diiron nonacarbonyl, Fe₂(CO)₉ at room temperature, leads to the iron carbonyl complexes of germanium(II) LGeFFe(CO)₄ (3) and tin(II) LSnFFe(CO)₄ (4), respectively. Compounds 3 and 4 were characterized by elemental analysis, NMR spectroscopy, and mass spectrometry. Furthermore, both complexes (3 and 4) were investigated by X-ray structural analysis which shows that both compounds are monomeric in the solid state containing terminal fluorine atoms.     

Samarium(II)-induced coupling of acid chlorides with allylic halides

Samarium(II)-induced coupling of acid chlorides with allylic halides gave diallylated tertiary alcohols. Monoallylated allylic ketones could not be obtained.     

Carbonyl allylations by 3-halopropenes or 2-propenyl mesylate with tin(IV) chloride and tetrabutylammonium iodide

2-Propenyl tin species, prepared from 3-halopropenes or 2-propenyl mesylate with tin(IV) chloride and tetrabutylammonium iodide in dichloromethane, causes nucleophilic addition to aldehydes to produce the corresponding homoallylic alcohols.     

Titanocene(II)-promoted carbonyl cyclopropylidenation utilizing 1,1-dichlorocyclopropanes

A variety of alkylidenecyclopropanes bearing various substituents on their cyclopropane ring were obtained by the titanocene(II)-promoted reaction of 1,1-dichlorocyclopropane derivatives with carbonyl compounds including esters and lactones.     

Interaction of tin (IV) chloride with sulfolane and between tin (IV) chloride and lithium chloride in sulfolane solution

Tin (IV) chloride reacts with sulfolane (S) to form a cis-octahedral adduct SnCl₄·S₂. Solutions of lithium chloride and tin (IV) chloride in sulfolane contain the complex ions SnCl ₅ ^– and SnCl ₆ ^2– at 11 and 21 mole ratios of constituents, respectively. The complexes are characterized by conductimetry and by Mössbauer, IR, and Raman spectroscopy.     

Nucleophilic (phenylsulfinyl)difluoromethylation of carbonyl compounds with difluoromethyl phenyl sulfoxide

We have successfully achieved nucleophilic (phenylsulfinyl)difluoromethylation of both enolizable and non-enolizable aldehydes and ketones by using difluoromethyl phenyl sulfone (1) as the fluoroalkylating agent. Although the chemical yields of the reactions are good to excellent, the observed diastereoselectivity is poor (dr = 1:1.04-2.03). The present synthetic methodology provides a convenient alternative for the preparation of α-(phenylsulfinyl)difluoromethylated carbinols that were previously synthesized via a two-step procedure.     

Separation of cobalt(II) from nickel(II) by solid-phase extraction into Aliquat 336 chloride immobilized in poly(vinyl chloride)

A solid-phase absorbent obtained by the immobilization of Aliquat 336 chloride in poly(vinyl chloride) is reported to extract preferentially Co(II) from its 7 M hydrochloric acid solutions containing Ni(II). Under the experimental conditions there was no extraction of Ni(II) which allowed the complete separation of these two ions. Co(II) was rapidly and quantitatively back-extracted with deionised water. A mechanism for the extraction of Co(II) is proposed based on the formation of the ion-pair A⁺[HCoCl₄]⁻ where A⁺ is the Aliquat 336 cation. Fe(III) and Cd(II), usually present in Co(II) and Ni(II) samples, were also extracted into the solid-phase absorbent though at a slower rate than Co(II) and they did not interfere with the separation of Co(II) from Ni(II). It was also demonstrated that this approach allowed the complete separation of Ni(II) from the other metal ions mentioned above.     

Inorganic tin(II) determination by FIA with amperometric detection of its oxinate complex

A highly selective, rapid and direct amperometric method, based on the formation of a complex between tin(II) and 8-hydroxyquinoline (oxine), has been developed for the determination of trace levels of tin(II) using flow injection analysis. Tin(II) electro-oxidation was catalyzed by oxine; its oxidation peak occurred at +0.05 V vs. Ag/AgCl at a glassy carbon electrode in 0.1 mol 1⁻¹ acetate buffer (pH 6). A linear relationship was obtained between the peak current and the tin(II) concentration in the range 0.25-20 μmol 1⁻¹. The detection limit was 0.1 μmol 1⁻¹ and the relative standard deviation calculated by the injection of a 10 μmol 1⁻¹ tin(II) solution was 5% (n = 20). Optimization of several experimental parameters has been carried out and the influence of numerous cations and possible interfering molecules encountered in radiopharmaceuticals and in dental gels has been investigated. The method was applied to the determination of tin(II) in dental gels.     

Cobalt(II)-catalyzed direct acetylation of alcohols with acetic acid

Cobalt(II) chloride hexahydrate (CoCl₂·6H₂O) efficiently catalyzes the acetylation of alcohols with AcOH in high yields. This protocol is also effective with other carboxylic acids, trifluoroacetic acid, propanoic acid, phenylacetic acid and benzoic acid, affording the corresponding acylated products in moderate to good yields. Removal of water is not necessary in these reactions. The catalyst can be filtered and recycled without loss of activity.     

Cyclopentadienyl-ruthenium(II) complexes as efficient catalysts for the reduction of carbonyl compounds

This work reports the reduction of a large variety of aldehydes and ketones with the system PhSiH₃/[CpRu(PPh₃)₂Cl] in good to excellent yields and high chemoselectivity. The catalyst [CpRu(PPh₃)₂Cl] can be used in at least 12 catalytic cycles with excellent catalytic activity and several substrates were reduced under solvent free conditions.     

Iridium-catalyzed carbonyl allylation by allyl ethers with tin(II) chloride

3-Alkoxypropenes, namely allyl ethers such as allyl butyl ether, allyl 2-hydroxypropyl ether, and diallyl ether, serve as reagents for the allylation of aldehydes with tin(II) chloride in the presence of a catalytic amount of [IrCl(cod)]₂ in THF and H₂O at 50 °C to produce the corresponding homoallylic alcohols.     

A novel tin (II) dithioether complex

Organotin and related tin containing compounds are a recurring motif in organometallic chemistry. Here we report a new complex resulting from the reaction of tin (II) chloride with a dithioether diallyl ether ligand created as a side product from other research in our lab. This new complex is reasonably stable and can be synthesized on the bench top with no extraordinary measures required to exclude air or moisture. Its crystal structure reveals a five coordinate pseudo-square pyramidal geometry around tin, with the ligand binding the metal through its thioether sulfurs and the chlorides bridging.     

Crystal structure and chemical bonding in tin(II) acetate

Tin(II) acetate was prepared and its crystal structure was solved from X-ray powder diffraction data. Tin(II) acetate adopts a polymeric structure consisting of infinite Sn(CH₃COO)₂ chains running along the c-axis which are packed into groups of four. The acetate groups bridge the Sn atoms along the chains. The Sn atoms are asymmetrically surrounded by four oxygen atoms with two short Sn–O distances (2.170(6), 2.207(6) Å) and two longer ones (2.293(7), 2.372(8) Å). The coordination environment of the Sn atoms is completed up to a strongly distorted trigonal bipyramid SnO₄E by the sterically active lone electron pair E. The coordination environment of the Sn atoms is virtually identical for Sn(CH₃COO)₂ in the gaseous and solid phase: the two short Sn–O bonds and the lone electron pair are located in the equatorial plane of the trigonal bipyramid and the two longer Sn–O bonds are directed towards the apical vertexes. Localization of the lone electron pair on Sn(II) was confirmed by electron localization function (ELF) analysis. The polymeric nature of the tin(II) acetate crystal structure was confirmed by a MALDI-TOF experiment.     

Synthesis and characterization of intermediate sitting-atop (i-SAT) complexes of free base meso-tetraarylporphyrins and tin(IV) chloride

The reaction of meso-tetraarylporphyrins (H₂T(X)PP) with SnCl₄ affords green intermediate sitting-atop (i-SAT) complexes, [(H₂T(X)PP)SnCl₄]. UV–Vis, ¹H NMR and ¹³C NMR spectral data show that the porphyrin core of the complexes is distorted, thus two nitrogen atoms of the pyrrolenine groups on one side of the porphyrin plane act as electron donors to the tin center of SnCl₄. The intermediate sitting-atop (i-SAT) complex is formed each time during the incorporation of the metal center, where in the intermediate state the pyrrolic protons still remain on the porphyrin.     

Carbonyl allylation of aldehydes catalyzed by a silica-supported poly-γ-diphenylarsinopropylsiloxane palladium(0) complex

A silica-supported poly-γ-diphenylarsinopropylsiloxane palladium(0) complex has been prepared from γ-chloropropyltriethoxysilane via immobilization on fumed silica, followed by reacting with potassium diphenylarsenide and palladium chloride, and then the reduction with hydrazine hydrate. The palladium(0) complex has been found to catalyze the allylation of aldehydes via the formation of π-allylpalladium complexes, using allylic chlorides as allylating agent and SnCl₂ as reducing agent. This polymeric palladium complex can be recovered and reused.     

An efficient and facile one-pot synthesis of cyanohydrin esters from carbonyl compounds catalyzed by iron(III) chloride

A variety of cyanohydrin esters were readily prepared from carbonyl compounds with trimethylsilyl cyanide and acid anhydride under the influence of a catalytic amount of iron(III) chloride in a convenient one-pot procedure.     

The first tin(II) vanadium(III) phosphate SnVPO5: Crystal structure and magnetic properties

The first tin vanadium phosphate SnVPO₅ was synthesized by a solid-state reaction and characterized by X-ray single crystal diffraction and magnetic susceptibility measurements. The crystal structure of SnVPO₅ (, , , α=113.283(11)°, β=108.037(9)°, γ=94.603(9)°, S.G. P-1, Z=2) is a three-dimensional framework constructed by V₂O₁₀ units fasten together by tetrahedral phosphate groups. Tin atoms are situated in structure interstices. They have five-fold coordination arrangement due to a presence of sterically active lone pair which position was visualized by ELF calculations. The magnetic susceptibility shows a broad maximum at 22 K which is probably due to low-dimensional spin correlations. We propose that the magnetism of the compound can be understood by interacting spin-dimers on a distorted square lattice. Strong quantum fluctuations were suggested by unusual field dependence of the transition temperature and unexpectedly low Curie constant.     

Expeditious oxidation of alcohols to carbonyl compounds using iron(III) nitrate

An efficient and solvent-free protocol for the oxidation of alcohols to corresponding carbonyl compounds using iron(III) nitrate nonahydrate has been developed.     

Copper(II)-catalyzed allylation of propargylic and allylic alcohols by allylsilanes: a facile synthesis of 1,5-enynes

Propargylic alcohols undergo smooth deoxygenative allylation with allylsilanes in the presence of a solution of 10 mol % of copper(II) tetrafluoroborate in acetonitrile to afford the corresponding 1,5-enynes in good to high yields under mild and neutral conditions. Scandium triflate is also found to catalyze efficiently the nucleophilic substitution of propargylic alcohols with allylsilanes.