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• Efficient aryl amination of azole compounds. • Coupling reaction employing reactive pseudo -halide. • TMP-iodonium(III) for reactive/selective aryl-transfer. It was determined that diaryliodonium(III) triflates bearing a trimethoxybenzene (TMP) auxiliary are more reactive than the reported selective aryl-transfer iodonium salts in the N -arylation of benzimidazoles and other types of azole compounds under catalytic conditions. The TMP-iodonium(III) salts can thus effectively facilitate the reaction at 50 °C or below, producing the corresponding N -arylated biaryls without the formation of TMP-derived coupling byproducts. Utilization of this TMP reagent under mild conditions would prevent the underlying problem of participation of the auxiliary group in the coupling reactions, which is observed while using the iodonium(III) salts that require elevated temperatures. [ABSTRACT FROM AUTHOR]

Arenes are rapidly converted to the corresponding iodides by aerobic oxidative iodination at room temperature by treatment with iodine and catalytic quantities of nitrous acid in a fluorinated solvent. Dichloroiodic acid is proposed as the actual iodination reagent. [ABSTRACT FROM AUTHOR]

The chemistry of hexacoordinate silicon complexes containing one or more pyridine-like ligands is reviewed. Pyridine-containing ligands are excellent ligands for stabilizing hexacoordinate silicon complexes, and over 100 hexacoordinate silicon complexes containing at least one pyridine-like ligand have been deposited with the Cambridge Structural Database. This review focuses on advances since 2000 and covers complexes with substituted pyridines, pyridine-2-thiolates, oxyquinolates, thioquinolates, iminoquinolates, bipyridines, phenanthrolines, and terpyridines. Emerging applications in fluorescence, high-energy materials, biology, and electrochromism are discussed. [ABSTRACT FROM AUTHOR]

A series of hypercoordinated monoorganotin dibromides formed by glycolic acid amides, [RSnBr 2 (OCH 2 C(O)NR′ 2 )] 2 ( 2a , R = Et, NR′ 2 = NMe 2 ; 3a , R = n- Bu, NR′ 2 = NMe 2 ; 4b , R = Ph, NR′ 2 = morpholin-4-yl), were obtained and investigated by X-ray analysis, multinuclear NMR spectroscopy in solutions ( 1 H, 13 C, 119 Sn) and solid state (CP/MAS). It has been established that 2a , 3a and 4b in solid state are dimeric. For the solutions in coordinating solvents the slow monomer–dimer equilibrium has been observed. The structures of related solvated monomeric chlorides, RSnCl(DMSO)(OCH 2 C(O)NR′ 2 ), 5a · DMSO and 6a · DMSO , were also investigated by X-ray analysis. [ABSTRACT FROM AUTHOR]

Herein we utilized, for the first time, sodium 2-iodoxybenzoate as a highly specific oxidant for PhthNH2 to create a highly chemoselective aziridination reagent. This method efficiently effects aziridination of electron-rich, electron-deficient, allylic alcohol and alkenyl bromide CC bonds in good to excellent yields. Inter and intramolecular chemoselectivity was demonstrated between electron-rich and electron-deficient alkenes by using this efficient and metal free protocol. [ABSTRACT FROM AUTHOR]

Abstract: Dithiastannecine compounds of the type [{ D (C6H4CH2S)2}SnR1R2] with different donor atoms D were prepared, where D =O and R1 =R2 =Ph (4a); R1 =Ph, R2 =Cl (5a); R1 = n-Bu, R2 =Cl (6a); D =S and R1 =R2 =Ph (4b); R1 =Ph, R2 =Cl (5b); R1 = n-Bu, R2 =Cl (6b). The molecular structures of the monochloro compounds 5a, 5b, 6a, and 6b were established by single-crystal X-ray diffraction and exhibit trigonal bipyramidal geometry at the tin atom with different degrees of distortion being due a D ⋯Sn interaction. The spiro compounds [{ D (C6H4CH2S)2}2Sn] with D =O (7a) and D =S (7b) were also synthesized and structurally characterized; the molecular structure of 7a showed the tin atom with a bicapped tetrahedral geometry. The behavior of all tin compounds in solution was investigated by NMR spectroscopy revealing that the D ⋯Sn interaction in solution was practically absent on the basis of the NMR chemical shifts values. DFT calculations with ADF package using VWN/QZ4P were carried out for the 6a and 6b compounds and showed that, in the topological analysis, bond critical points are present along the D ⋯Sn direction. [Copyright &y& Elsevier]

Abstract: D(CH2CH2S)2MSNH(C6H4) (M=Ge, Sn; D=O, S) spirocycles were synthesized to analyze the influence of the decrease of the radius of the metal and the change of the hardness of donor atom on the strength of the transannular bond and the hypercoordination of group 14 elements. The compounds were characterized by IR, Raman and NMR (1H, 13C and 119Sn) spectroscopy, EI mass spectrometry and elemental analysis. Monocrystal X-ray diffraction analyses were made for the germanium compounds. The germaspirocycles were five-coordinated and had distorted trigonal bipyramid geometry. In contrast with most of the reported analogous germocanes, the transannular bond is stronger when the donor atom is oxygen, rather than sulfur. O(CH2CH2S)2GeSNH(C6H4) exhibits an intramolecular hydrogen bond formation between the amine group and the transannular oxygen. The presence of this hydrogen bond determines whether the sulfur (O⋯Ge–S) or the nitrogen (S⋯Ge–N) of the five-member ring is the axial atom. According to the 119Sn chemical shift, both stannospirocycles were five-coordinated and therefore the presence of the transannular interaction in solution could be suggested. [Copyright &y& Elsevier]

Abstract: Treatment of Ph2SnCl2 with S(C6H4SH)2 in benzene leaded to the formation of [{S(C6H4S)2}SnPhCl] (1); the same reaction with 1,4-diazabicyclo-[2.2.2]-octane leaded [{S(C6H4S)2}SnPh2] (4). The compounds [{S(C6H4S)2}SnPhHal] (Hal=Br, 2; I, 3) have been synthesized by halogen exchange from 1 and the corresponding potassium halide. The compound [{S(C6H4S)2}SnCl2] (5) was obtained from S(C6H4SH)2 and SnCl4. The reaction of 1 with NaS2CNEt2·3H2O yielded [{S(C6H4S)2}SnPh{S2CNEt2}] (6). X-ray structure determinations of dibenzostannocines 1–6 revealed that the tin atom acts as an acceptor atom displaying an intramolecular transannular interaction with the sulfur (thioether-like) atom. The local geometry of the Sn atom in the compounds 1–5 is described as distorted trigonal bipyramidal with a TBP character spanning from 81% to 73%. In 6 the tin atom is six-coordinate with a distorted octahedral geometry. [Copyright &y& Elsevier]

Abstract: Treatment of R n GeCl4− n with {S(C6H3SH)2O} (1) afforded the stable phenoxathiin-4,6-dithiolate compounds [{S(C6H3S)2O}GeR2] [n =2; R=Et (2), Ph (3)] and [{S(C6H3S)2O}GeRCl] [n =1; R=Et (4), Ph (5)]. Treatment of GeCl4 with 1 in benzene afforded the dichloro compound [{S(C6H3S)2O}GeCl2] (8) at 7°C. Bromo compounds [{S(C6H3S)2O}GeRBr] [R=Et (6), Ph (7)] and [{S(C6H3S)2O}GeBr2] (9) were synthesized by halogen exchange from the appropriate chloro derivative using KBr/HBr. X-ray structure determinations of diorganyl dithiolate compounds 2 and 3 revealed that germanium atom is contained in a boat–chair-shaped eight-membered central ring and displays a tetrahedral geometry. In contrast, compounds 4–6 display a boat–boat-shaped central ring with a significant intramolecular transannular O···Ge interaction. The geometry of the pentacoordinate Ge atom in these last complexes may be described as distorted trigonal bipyramidal with a 62–65% distortion displacement. [Copyright &y& Elsevier]

Abstract: Addition of M2SCN(CH2R)2 to D(C6H4S)2SbCl in methylene chloride solution leaded to the formation of the stable compounds D(C6H4S)2SbS2CN(CH2R)2 (D=O, R=Me, 1; D=S, R=Me, 2; R=Ph, 3). The new dibenzostibocines derivatives containing two different types of dithioligands were characterized by elemental analysis and spectroscopic studies (IR, 1H and 13C NMR). Single crystal X-ray diffraction determinations of complexes 1–3 revealed that the antimony atom acts as an acceptor atom exhibiting an intramolecular transannular interaction with the donor D atom, expanding its coordination from three to five and displaying a skew trapezoidal local geometry. [Copyright &y& Elsevier]

Abstract: Reaction of [2,6-(MeOCH2)2C6H3]Li (1) with SbCl3 in 1:1 molar ratio yielded except the intended product [2,6-(MeOCH2)2C6H3]SbCl2 (2) unexpected complex 3 consisting of antimony anion [Sb6Cl22]4− compensated by four intramolecularly coordinated organoantimony cations [2,6-(MeOCH2)2C6H3]2Sb+. Compound 3 is labile in CH2Cl2(CHCl3) solution and decomposes to compound 2 and SbCl3. Both compounds were characterized by the help of 1H and 13C NMR spectroscopy, ESI-mass spectrometry and in the case of 3 by single crystal X-ray diffraction techniques. [Copyright &y& Elsevier]

Abstract: Silyl tellurides reacted with alkyl halides under mild thermal conditions to give the corresponding alkyl tellurides and silylhalides in good to excellent yields. Substitution took place much faster in polar solvents, such as acetonitrile, than that in non-polar solvents. After removal of the volatile silyl halides and solvent under vacuum, the essentially pure divalent organotellurium compounds were obtained. Theoretical calculations were performed to understand the reaction mechanism, and a stepwise pathway involving tetravalent organotellurium intermediate was obtained. Since the intermediate as well as the rate-determining step leading to the intermediate from the reactants possess highly polar character, they would be stabilized in polar solvents. [Copyright &y& Elsevier]

Abstract: New liquid crystals with a pentafluorosulfanyl function as their polar terminal group were prepared and fully characterized. The synthetic key step was the triethyl borane-catalyzed addition of SF5Br to a suitable olefin precursor, followed by dehydrobromination. The most interesting characteristic of the new materials is their combination of high polarity (Δɛ) with very low birefringence (Δn), which is of particular importance for LCDs for mobile applications. [Copyright &y& Elsevier]

Abstract: Phosphonium salts as a novel metal-free Lewis acid catalyst can be considered as organocatalysts. The introduction of a five-membered dioxaphosphacycle to the phosphonium salt is critical to its function as a Lewis acid catalyst for the Diels–Alder reaction. The key to the successful catalysis by the phosphonium salt is the utilization of hypervalent bonding as a strategic interaction for the generation of an active species. [Copyright &y& Elsevier]

Abstract: The 1-oxa-4,6-dithia-, 1,3,6-trithia-, 1-aza-4,6-dithia-, 1-aza-4,6-dioxa-, 1-thia-4,6-dioxa- and 1,3,6-trioxametallocanes possess a strong 1,5 transannular interaction through an acceptor atom M [Ge(IV), Sn(IV), Pb(IV), As(III), Sb(III) and Bi(III)] and an X donor (O, S, NR). The conformation adopted by the metallocane ring has exhibited various conformations along with the extreme conformations boat–boat, boat–chair and chair–chair. The structural diversity observed in these eight-membered rings results in a variety of coordination numbers, as well as in the presence of polymeric structures. The purpose of the present review is to highlight the relationship between the strength of the transannular bonding and the resulting molecular structures. Factors such as coordination number, electronegativity and steric effects are revised. [Copyright &y& Elsevier]

Title compounds containing tetracoordinate sulfur, pentacoordinate sulfur, tetracoordinate selenium and tetracoordinate tellurium together with oxygen or nitrogen were successfully synthesized as stable compounds. Some compounds have the Martin ligand that is well-known to stabilize such high coordinate main group compounds, while others have another four-membered ring. X-ray crystallographic analyses revealed that the compounds have distorted trigonal bipyramidal (TBP) or pseudo TBP structures. In marked contrast to group 13–15 element analogues, which afford the corresponding olefins on heating, their thermolyses gave the corresponding oxiranes or an aziridine except for a few 1,2-oxachalcogenetanes, suggesting the possibility that these compounds are intermediates of the Corey–Chaykovsky reaction of chalcogen ylides with carbonyl compounds or imines. The stereochemistry (retention of configuration) of some oxirane formation reactions as well as compounds synthesized by other groups is also described. [Copyright &y& Elsevier]

Abstract: We have found that the use of the PhI(OAc)2/Et4N+Br− combination in water can significantly enhance its oxidation ability and oxidize a wide range of alcohols 1 to carbonyl compounds 2 in good to excellent yields. This clean aqueous oxidation method shows no detectable racemization processes, and even an enolizable ketone 2m could be obtained in an optically pure form from the corresponding chiral alcohol 1m. Utilization of the recyclable reagent 3 as a more practical alternative to PhI(OAc)2 is also successful in these reactions. [Copyright &y& Elsevier]