Well-defined Cu(I) complexes based on [N,P]-pyrrole ligands catalyzed a highly endoselective 1,3-dipolar cycloaddition.

We herein report the synthesis and catalytic application of a new family of dinuclear Cu(I) complexes based on [N,P]-pyrrole ligands. The Cu(I) complexes (4a-d) were obtained in good yields and their catalytic properties were evaluated in the1,3-dipolar cycloaddition of azomethine ylides and electron-deficient alkenes. The air-stable complexes 4a-d exhibited high endo-diasteroselectivity to obtain substituted pyrrolidines, and the catalytic system showed excellent reactivity and wide substitution tolerance.

Two-photon isomerization properties of donor-acceptor Stenhouse adducts.

Donor-acceptor Stenhouse adducts (DASAs) are important photo-responsive molecules that undergo electrocyclic reactions after light absorption. From these properties, DASAs have received extensive attention as photo-switches with negative photochromism. Meanwhile, several photochemical applications require isomerization events to take place in highly localized volumes at variable depths.

Synthesis of (μ,η-allyl-η-oxapentadienyl)diiron pentacarbonyl complexes, an unusual reaction product from η-(vinylketene)Fe(CO) complexes: structure and electron density distribution analysis.

The synthesis of a series of ferrocenylvinylketenes as stable η-[Fe(CO)] complexes (3a-f) was successfully accomplished through the reaction of η-[Fe(CO)] complexes under mild carbonylation conditions. The reactivity of 3a-f under thermal conditions afforded the unexpected formation of a novel family of (μ,η-allyl-η-oxapentadienyl)diiron pentacarbonyl complexes 5a-f proposed to be formed by a sequence metathesis-haptotropic rearrangement between the starting η-vinylketene iron(0) complex 3 and a η-vinylcarbene iron(0) complex trapped after a reversible carbonylation process favored by the thermal conditions. An electron density distribution analysis (EDD) of 5e using high-resolution X-ray diffraction data in combination with the DFT framework was performed to understand the electronic communication between the two iron fragments.

Iodine-promoted insertion of the oxygen atom from water in η-vinylketene[Fe(CO)] complexes.

Iodine promotes the formation of iron(II) species from η-vinylketene[Fe(CO)] (3a-h) as a key intermediate for the synthesis of 2(5)-furanones (4a-h) by a sequential water-insertion/carbon-oxygen coupling under mild reaction conditions. Compounds 4a-h were obtained in good to excellent yields. A possible reaction pathway was also proposed by DFT calculations.

Interrupted Intramolecular Hydroaminomethylation of -Protected-2-vinyl Anilines: Novel Access to 3-Substitued Indoles or Indoline-2-ols.

A new synthetic alternative to the synthesis of 3-methyl indoles and 3-methyl indoline-2-ols with an excellent atomic economy is presented in this study. It is demonstrated that the intramolecular interrupted hydroaminomethylation (HAM) reaction is a powerful tool for the formation of these compounds, which exhibit wide-ranging biological activity. Several -Protected-2-vinyl anilines were synthesized and involved in the reaction producing the corresponding 3-methylindole or 3-methyl indoline-2-ol depending on the nature of the -protecting groups.

2-Thiazolines: an update on synthetic methods and catalysis.

2-Thiazolines are important building blocks in organic synthesis and are of great importance in many areas of chemistry. At the end of the last century, the use of 2-thiazolines increased in a significant way, especially in synthesis and catalysis. This review highlights the synthetic and catalytic value of 2-thiazolines in the last two decades.

Two-photon induced isomerization through a cyaninic molecular antenna in azo compounds.

We present a new design for non-linear optically responsive molecules based on a modular scheme where a polymethinic antenna section with important two-photon absorption properties is bonded to an isomerizable actuator section composed of a stilbenyl-azopyrrole unit. Upon two photon excitation, energy migration from the antenna-localized second singlet excited state to the stilbenyl-azopyrrole section allows for efficient indirect excitation and phototransformation of this actuator.

Antifungal and antioomycete activities and modes of action of isobenzofuranones isolated from the endophytic fungus Hypoxylon anthochroum strain Gseg1.

Hypoxylon species are distributed worldwide and have been isolated from different habitats. The endophyte Hypoxylon anthochroum strain Gseg1 was isolated from healthy leaves of Gliricidia sepium. A chemical study of the culture medium and mycelium organic extracts of the endophytic fungus H.

Aluminum complexes with new non-symmetric ferrocenyl amidine ligands and their application in CO transformation into cyclic carbonates.

A set of alkyl aluminum complexes supported by non-symmetric ferrocenyl amidine ligands were used as catalysts for the preparation of cyclic carbonates from epoxides and carbon dioxide using Bu4NI as a co-catalyst. A modified method for the synthesis of aminoferrocene allowed us to obtain this precursor in quantitative yield. Treatment of aminoferrocene with the corresponding acetimidoyl chloride afforded the desired ferrocenyl amidine ligands L1H, (E)-N-(2,6-diisopropylphenyl)-N'-(ferrocenyl)acetimidamide, and L2H, (E)-N-(2,6-dimethylphenyl)-N'-(ferrocenyl)acetimidamide.

Nanostructured Thin Films Obtained from Fischer Aminocarbene Complexes.

The synthesis of four amphiphilic organometallic complexes with the general formula RC = M(CO)₅NH(CH₂)CH₃, where R is a ferrocenyl 2(a-b) or a phenyl 4(a-b) group as a donor moiety and a Fischer carbene of chromium (0) or tungsten (0) as an acceptor group, are reported. These four push-pull systems formed Langmuir (L) monolayers at the air-water interface, which were characterized by isotherms of surface pressure molecular area and compression/expansion cycles (hysteresis curves); Brewster angle microscopic images were also obtained. By using the Langmuir-Blodgett (LB) method, molecular monolayers were transferred onto glass substrates forming Z-type multilayers.

An expedient approach to synthesize fluorescent 3-substituted 4H-quinolizin-4-ones via (η(4)-vinylketene)-Fe(CO)3 complexes.

An efficient and practical methodology for the synthesis of 3-substituted 4H-quinolizin-4-ones using (η(4)-vinylketene)-Fe(CO)3 complexes as key intermediates has been developed. The advantage of this transformation lies in the use of simple and readily available starting materials and mild carbonylation conditions. The fluorescent properties of these compounds were determined and the quantum yield was obtained, ranging from 0.

2-Ferrocenyl-2-thiazoline as a building block of novel phosphine-free ligands.

New 1,2-disubstituted ferrocenes [5(b-j), in which R = -SMe, -SPh, -SiPr, -SiMe3, -SePh, -SnBu3, -B(OH)2, -Me, -I] with a thiazoline ring in the ferrocene backbone using as key intermediate a ferrocenyl Fischer carbene complex were synthesized. The capability of the 2-thiazoline moiety as an ortho-directed metalation group was demonstrated by subsequent quenching of lithium intermediate with several electrophiles, proving to be an excellent method for synthesizing bidentate ligands. The catalytic scope of the [N,S] ligand 5b as the corresponding palladium complex 5b-PdCl(2) in a microwave-promoted Heck reaction was also tested.

Synthesis of Fischer type-carbene complexes containing a coordinated thioimidate structural motif.

This paper describes a tandem strategy to synthesize a series of new Fischer carbene complexes [(CO)(4)M=C[N-(CH(2))(4)-]CH=C(NRR')(SR'); M = Cr, W; R = Ar, R' = Me, -(CH(2))(2)-] with a thioimide or thiazoline fragment, in which the sulfur or nitrogen atom is coordinated to a metal center, depending on the nature of alkylating groups included as R'. We have trapped by protonation the proposed intermediate as the thioamide 12 [(CO)(5)W=[N-(CH(2))(4)-]CH(2)C(S)NHPh], which reveals the pathway of this reaction.

Ferrocenylselenoamides: synthesis, characterization and cytotoxic properties.

A new series of ferrocenyl selenoamides 7-11 (FcSeNH(CH(2))(n)CH(2)(R)OH, n = 1, 2, 3, R = H, Me, Ph) were prepared in good yields by selenative demetalation of Fischer aminocarbene complexes. The crystal structures of 7 [FcSeNH(CH(2))(2)OH] and 19 [PhSeNH(CH(2))(2)OH] reveal their capability to form intermolecular hydrogen bonding in solid state. Results of SRB assays show that these new selenium compounds have a good anticancer potency superior to tamoxifen and cisplatin, with IC(50) values ranging from 4.

Three new enantiomerically pure ferrocenylphosphole compounds.

The absolute configurations of three new enantiomerically pure ferrocenylphosphole compounds, namely (2S,4S,S(Fc))-4-methoxymethyl-2-[2-(9-thioxo-9lambda5-phosphafluoren-9-yl)ferrocenyl]-1,3-dioxane, [Fe(C5H5)(C23H22O3PS)], (III), (S(Fc))-[2-(9-thioxo-9lambda5-phosphafluoren-9-yl)ferrocenyl]methanol, [Fe(C5H5)(C18H14OPS)], (V), and (S(Fc))-diphenyl[2-(9-thioxo-9lambda5-phosphafluoren-9-yl]ferrocenylmethyl]phosphine, [Fe(C5H5)(C30H23P2)], (VIII), have been unambiguously established. All three ligands contain a planar chiral ferrocene group, bearing a dibenzophosphole and either a dioxane, a methanol or a diphenylphosphinomethane group on the same cyclopentadienyl. In compound (V), the occurrence of O-H.

Synthesis and characterization of novel dinuclear copper(I) complexes. Dimerization of [CuL(PPh3)2] (L = methyl 3-hydroxy-3-(p-R-phenyl)-2-propenedithioate).

We report the synthesis of new copper(I) complexes 6a-e from methyl 3-hydroxy-3-(p-R-phenyl)-2-propenedithioate ligands. These complexes were characterized by IR and 1H, 13C, and 31P NMR spectroscopy. The expected O,S-coordination mode was confirmed by the X-ray diffraction studies of 6b and 6e.

Synthesis, characterization, and tautomerism of four novel copper(I) complexes from 3-hydroxy-3-(p-R-phenyl)-2-propenedithioic acids.

The paper describes the synthesis and structural characterization of four novel copper(I) complexes [CuL(PPh(3))(2)] (L = 3-hydroxy-3-(p-R-phenyl)-2-propenedithioate). In addition, a tautomeric equilibrium in solution was found and Hammett correlations with (13)C NMR parameters were studied. The structure of one complex was fully established by X-ray diffraction analysis.