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[Display omitted] Ethanol over calcium stannate (CaSnO 3) catalyst under supercritical conditions (400 °C, 120 atm) is transformed mainly into ethanal, ethyl acetate and 2-buten-1-ol. The process is accompanied by crystallization of the amorphous catalyst. [ABSTRACT FROM AUTHOR]

A new family of benzimdazolin-2-iminato actinide−(IV) complexes [(Bim 7-Me Dipp/Me N)An(N(SiMe 3 ) 2 ) 3 ] (An = U ( 3 ), Th ( 4 )) and [(Bim 4-Me Dipp/Me N)An(N(SiMe 3 ) 2 ) 3 ] (An = U ( 5 ), Th ( 6 )) were synthesized and their solid state structures were established by single-crystal X-ray diffraction analysis. The catalytic performances of complexes 3 – 6 towards the homo- and cross-coupling of aldehydes (Tishchenko reaction) were studied and the thorium complexes 4 and 6 displayed moderate to high activities for the production of the corresponding symmetric and unsymmetrical esters. Coupling of aldehyde and alcohols, known as the tandem proton-transfer esterification, and the intermolecular coupling reaction between aldehyde and trifluoromethylketones were also investigated by these thorium complexes, indicating a complementary method to obtain unsymmetrical esters selectively. Plausible mechanisms for these reactions are proposed based on stoichiometric studies. [ABSTRACT FROM AUTHOR]

The catalytic asymmetric synthesis of (−)-arctigenin is reported. The central optically pure lactone intermediate is obtained either from an Ir-catalyzed asymmetric Tishchenko reaction or an asymmetric oxidative lactonization and subsequently converted to β-iodomethyl-α-methylene-γ-butyrolactone. Several recent Negishi coupling protocols were investigated for the introduction of an aryl unit in the presence of the α-methylene-γ-butyrolactone. The introduction of a second aryl unit was achieved using a diastereoselective Rh-catalyzed conjugate addition and protonation under protecting-group-free conditions. [Display omitted] [ABSTRACT FROM AUTHOR]

Four aluminum alkoxide complexes containing β-hydroxy-imino ligands, [(2,6-Me 2 C 6 H 3 )NCPhCH 2 CPh 2 O] 2 AlMe ( 3a ), [(2,6- i Pr 2 C 6 H 3 )NCPhCH 2 CPh 2 O] 2 AlMe ( 3b ), [(2,6-Me 2 C 6 H 3 )NCPhCH 2 C(C 12 H 8 )OAlMe 2 ] 2 ( 3c ) and [(2,6- i Pr 2 C 6 H 3 )NCPhCH 2 C(C 12 H 8 )OAlMe 2 ] 2 ( 3d ) were synthesized in high yields, and their structural features were provided. The catalytic behavior of those four complexes about the Tishchenko reaction with a range of aromatic aldehydes as substrates were assessed, and it present a synthetically useful protocol to the solvent-free Tishchenko reaction under mild conditions. [ABSTRACT FROM AUTHOR]

Bulky guanidinate stabilized homoleptic complexes of [LM(thf) n L] [L = {ArNC (N i Pr 2 )NAr} (Ar = 2,6- Me 2 –C 6 H 3 )]; M = Mg, Ca, and Zn; n = 0–1) have been synthesized with three different synthetic routes. First, treatment of bis{bis(trimethylsilyl)amide}s of Mg, Ca, and Zn i.e. [M{(N(SiMe 3 ) 2 } 2 ] (M = Mg, Ca(thf) 2 , and Zn) with free guanidine ligand (LH) at 80 ° C, elimination of NH(SiMe 3 ) 2 and formation of [LM(thf) n L] (M = Mg, Ca and Zn; n = 0–1) ( 3 – 5 ) complexes were occurred. Second, the reaction of two equivalents of potassium salt of LH with metal dihalides via salt metathesis led to the formation of homoleptic complexes. Third, the reaction between MR 2 (M = Mg, Ca, Zn; R = alkyl or OTf) and LH at reflux temperature, formation of bis(guanidinate) magnesium, calcium, and zinc complexes have been observed. The solid state structures of LH( 1 ), LK( 2 ) and all three bis(guanidinate) magnesium, calcium and zinc complexes ( 3 – 5 ) were confirmed by X-ray structural analysis. Furthermore, dimerization of a range of aromatic, heteroaromatic and aliphatic aldehydes (Tishchenko reaction) has been demonstrated by using catalysts 3 – 5 . [ABSTRACT FROM AUTHOR]

The dimerization of aldehydes to the analogous carboxylic esters (Tischenko reaction) has been achieved in impressive yields using the dilithium compounds containing bidentate di-anionic pyrrolyl ligands as initiators. The initiated intermediate {[2-( t BuNCH)C 4 H 3 NLi][PhCH 2 OLi(TMEDA)]} 2 was isolated and characterized by satisfactory C, H and N microanalysis, 1 H, 13 C{ 1 H} and 7 Li NMR spectra in pyridine-d 5 at ambient temperature, and single crystal X-ray structural data. The processes involve a redox reaction of 2-aminopyrrolyl dilithium compound with aldehyde. [ABSTRACT FROM AUTHOR]

Three amidinatoaluminum compounds, [{MeC(NCy) 2 }AlMe(μ-OMe)] 2 ( 1 ), [{(PhN)MeC(NCy)}AlMe(μ-OMe)] 2 ( 2 ) and [{(PhN)MeC(N t Bu)}AlMe(μ-OMe)] 2 ( 3 ), were prepared by the insertion reaction of oxygen with the corresponding aluminum amidinate in high yield and characterized by 1 H and 13 C NMR spectra and single crystal X-ray diffraction analysis. 1 – 3 were used as pre-catalysts to catalyze the Tishchenko reaction and both 2 and 3 exhibited good to excellent catalytic activity under mild conditions. [ABSTRACT FROM AUTHOR]

Redox transmetallation/protolysis reactions were employed to synthesize a series of the rare earth bis(aryl)formamidinate complexes. Trivalent complexes were synthesized with three chelating formamidinate ligands about the metal centers. A study of the reactivity towards the Tishchenko reaction shows the compounds catalyse the Tishchenko reaction in the formation of esters from aldehydes. [Display omitted] • The chemistry we present here extends our studies of rare earth formamidinato chemistry and their applicability in Tishchenko catalysis. • The chemistry presented should be of great interest to inorganic and organometallic chemists, and more specifically to those with interests in f-block chemistry. Furthermore, due to the great interest in cyclopentadienyl replacement chemistry in rare earth studies more broadly, this chemistry will appeal to most synthetic and structural chemists. • We therefore think that Inorganica Chmica Acta is the right platform to publish our results to rapidly spread our findings to the inorganic chemical community. • We look forward to hearing from you soon regarding this submission. Redox transmetallation/protolysis reactions of rare earth metals, Hg(C 6 F 5) 2 and a formamidine (PhFormH = N , N '-(diphenyl)formamidine or DMFormH = N , N ' -bis(2,4-dimethylphenyl)formamidine) in tetrahydrofuran (thf) or 1,2-dimethoxyethane (dme) were employed to synthesize a series of the rare earth N,N' -bis(aryl)formamidinate complexes. Accordingly, trivalent complexes with the composition [Ln(PhForm) 3 (thf) n ]⋅(solv.) m [n = 2, m = 0, Ln = La (1), Pr (2); n = 2, m = 0.5, solv = thf, Sm (3); n = 2, m = 1.5, solv. = PhMe, Ln = Nd (4); n = 2, m = 1.5, solv. = thf, Ln = Gd (5); n = 2, m = 3, solv. = thf, Ln = Tb (6), Dy (7), and Y (8); n = 1; m = 0, Ln = Ho (9), Er (10) and Lu (11)] or [Ln(DMForm) 3 (solv.)] [Ln = Sm (12), Gd (13), solv. = dme; Ln = Pr (14), Ho (15), solv. = DMFormH; Ln = Y (16), Lu (17), solv. = thf; Ln = Er (18), solv. = dmf; dmf = N,N -dimethylformamide] were synthesized and characterized by X-ray crystallography. Complexes 1 – 8 have eight coordinate Ln metals with three chelating PhForm and two transoid thf ligands, whilst 9 – 11 are seven coordinate with a single thf ligand. Thus, there are three structural discontinuities, namely at Ho, Y, Er, the second of which occurs in defiance of a decrease in ion size. An investigation of catalytic reactivity of representative Ln complexes in the conversion of aldehydes into esters (Tishchenko reaction) revealed most have modest catalytic properties. [Y(PhForm) 3 (thf) 2 ]⋅3thf 7 and [Y(DMForm) 3 (thf)] 16 had the highest reactivity for their respective ligands, with 16 by far the most effective catalyst. [ABSTRACT FROM AUTHOR]

Abstract: Aliphatic aldehydes react with catalytic amount of Dibal-H in n-pentane to give the corresponding Tishchenko products in good to excellent yields. On contrary, α-silyloxy aldehydes give α-silyloxy ketones via Oppenauer oxidation under similar condition. Tishchenko reaction of ω-alkene aldehydes followed by RCM and hydrogenation affords a convenient method to prepare the 11–37 membered macrocyclic lactones. [Copyright &y& Elsevier]

Abstract: Tishchenko reaction of benzaldehyde was carried out over the MgO whose surface O atoms were enriched with 18O to examine whether the surface O atoms of MgO are incorporated into the product and reactant. The surface lattice 18O atoms were incorporated in both the product and reactant. The 18O concentration was significantly higher for the product than for the reactant. In addition, the 18O in the product ester was located not only in the carbonyl group (Cso in the bridging position (Ch name="sbnd" />C); 18O exchange between benzaldehyde and MgO surface occurred not only in the adsorption–desorption of benzaldehyde, but also in the dimerization process. The oxygen exchange results in the migration of active sites of coordinative unsaturated site (CUS) over the surface of MgO catalyst during the reaction. [Copyright &y& Elsevier]

Abstract: Treatment of mesoporous silicate SBA-15 with Sm[N(SiMe3)2]3 led to the formation of a novel organolanthanide/inorganic hybrid material [SBA-15]Sm[N(SiMe3)2] x via abstraction of N(SiMe3)2 by terminal silanol groups and subsequent surface silylation. The hybrid material was characterized by elemental analyses, IR spectroscopy, X-ray diffraction, and nitrogen sorption, indicating a successful tailoring inside the silicate SBA-15 and the maintenance of the well-ordered mesostructure. This hybrid material is a promising heterogeneous catalyst for the Tishchenko reaction, where it is superior to the homogeneous correspondent in deactivation behavior, reusability and relative tolerance to oxygen, particularly in the control of selectivity of mixed Tishchenko reaction due to the steric hindrance and the diffusion control derived from the surface confinement. [Copyright &y& Elsevier]

Abstract: i-PrOZnEt is an excellent reagent to promote the aldol-Tishchenko reaction of the aliphatic aldehydes tethered with other labile functional groups. The 1,3-diol monoesters 4 were formed as the major products, which could be converted to α-methylene ketones 7 in two steps in good yields. [Copyright &y& Elsevier]

[RuCl(SiMe3)(CO)(PPh3)2] (1) was found to catalyze dimerization of aldehydes RC(O)H yielding esters RC(O)—OCH2R (3) in a Tishchenko type reaction. Aldehydes with α-hydrogen atoms (R = Me, Et, iPr, iBu) reacted quantitatively within 2 days (5 mol% catalyst, 70 °C in C6D6) whereas those without α-hydrogen atoms (R = tBu, Ph) did not react at all. In the case of benzaldehyde (R = Ph), well shaped crystals of [RuCl(O2CPh)(CO)(PPh3)2] (4) precipitated from the reaction mixture. Molecular structures of catalyst 1 and benzoato complex 4 were established by single-crystal X-ray diffraction analyses exhibiting square pyramidal (1) and octahedral (4) complex, respectively. Using 1:1 mixture of acetaldehyde and propanal a crossed esterification reaction took place forming esters RC(O)—OCH2R′ (3, R/R′ = Me/Me, Et/Et; 5, R/R′ = Me/Et, Et/Me). In the case of tBuC(O)H a crossed esterification reaction with RC(O)H (R = Me, Et) took place yielding only two products, namely the symmetrical esters RC(O)—OCH2R (3, R = Me, Et) and the crossed products of the type RC(O)—OCH2tBu (6, R = Me, Et). As shown with propanal, ester formation is completely suppressed by water. Because ruthenium catalyst 1 was prepared by reaction of [RuCl(H)(CO)(PPh3)3] (2) with H2C = CHSiMe3, complex 2 was also used as catalyst in the reaction with aldehydes. It proved to be non-active, but in the presence of H2C=CHSiMe3 (H2C=CHSiMe3:RC(O)H = 1:1) catalytic formation of cyclotrimers of aldehydes (RCHO)3 (7) and aldol condensation products RCH=CR′—C(O)H (8, R = Et, iBu; R′ = R−CH2) was observed. [Copyright &y& Elsevier]

• Sodium organoaluminate stabilized by bidentate pyrrolyl ligand was synthesized. • The X-Ray diffraction analyses reveal it is a 1D infinite chain structures. • It could be applied to the crossed-Tishchenko reaction of aromatic aldehyde. An novel sodium organoaluminate containing bidentate pyrrolyl ligand [C 4 H 3 NH(2-CH 2 NHtBu)] was efficiently synthesized and characterized by X-ray crystallography. The molecular structure shows it is a monodimensional infinite chain structures with linear arrangements. Its basic repeat unit comprises the Al atom bonded to two deprotonated pyrrole rings and Na atom coordinated to of nitrogen atoms of –NtBu fragment, which undergoes further to coordinates a pyrrolyl ring of an adjacent molecule in a ƞ2-fasion. Furthermore, this sodium organoaluminate exhibited high catalytic activities for Tishchenko reaction. [Display omitted] [ABSTRACT FROM AUTHOR]

The aliphatic aldehydes react with catalytic amount of Dibal-H in n-pentane to give the corresponding Tishchenko products in good to excellent yields. Contrary, α-silyloxyaldehydes give α-silyloxyketones via Oppenauer oxidation under similar condition. [Copyright &y& Elsevier]

Isopropoxyaluminum 1,1′-biphenyl-2-oxy-2′-perfluorooctanesulfonamide (3) has been evaluated as an aluminum-based catalyst for the Tishchenko reaction. Compound 3 was found to exert high catalytic activity in the reaction with aliphatic aldehydes and also enabled smooth dimerization of enolizable aldehydes. This advantage was highlighted by the quantitative formation of ethyl acetate from acetaldehyde by the present system. [Copyright &y& Elsevier]