A direct, efficient, and highly chemoselective synthesis of saturated alcohols through one-pot sequential 1,4- and 1,2-reduction of cyclic and acyclic conjugated ketones is reported. The saturated alcohols are obtained in very good yields using sodium borohydride (NaBH4) as a reducing agent and a catalytic amount of copper(I) cyanide (CuCN) in ethanol as a green solvent. This nontoxic solvent significantly favors full 1,4-reduction, as opposed to methanol. Selectivity is further enhanced by the combination of two additives (a lithium salt or a sodium salt, such as NaI).

The Cover Feature shows a redox-active complex combining phenols and oxamato units. Two phenol units (Schiff base, aminophenol) and two metal ions (copper, nickel) were used, but, whatever the structure, the oxidation is ligand-centered, affording phenoxyl radical species. Hence the oxamato linker does not orientate the oxidation site towards the metal. Counter-intuitively, the Schiff base is easier to oxidize than the aminophenol derivative. Both copper complexes catalyze the oxidation of benzyl alcohol into benzaldehyde and benzoic acid, albeit with different time scales. More information can be found in the Research Article by O. Jarjayes, F. Thomas and co-workers.

The copper and nickel complexes of two tetradentate ligands derived from bis(aminophenol) and bis(phenol) architectures connected by an oxamate linker were isolated. Depending on the metal and ligand, the complex is isolated with either an intact (deprotonated) ligand (1(2-)), one-electron oxidized ligand (2(-)) or quinone form (3). Surprisingly, the Mannich base is easier to oxidize than the amidophenol derivatives. The complexes were characterized by X-ray diffraction, cyclic voltammetry, UV-Vis-NIR and EPR spectroscopies. Complex 1 shows two reversible oxidation waves assigned to the successive iminosemiquinone/aminophenolate redox systems. Complex 2(-) shows an intense NIR feature, as well as an EPR signal at g(iso)=2.043, consistent with a metallic contribution to the main ligand radical SOMO. Complex 3 shows the typical feature of an isolated Cu(II) complex. Spectro-electrochemistry coupled to DFT calculations demonstrate a ligand-centered oxidative redox chemistry for all the complexes.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

During the last decade, the evidence for the biological relevance of i-motif DNA (i-DNA) has been accumulated. However, relatively few molecules were reported to interact with i-DNA, and a controversy concerning their binding mode, affinity, and selectivity persists in the literature. In this context, the cholestane derivative IMC-48 has been reported to modulate bcl-2 gene expression by stabilizing an i-motif structure in its promoter. In the present contribution, we report on a novel, more straightforward, synthesis of IMC-48 requiring fewer steps compared to the previous approach. Furthermore, the interaction of IMC-48 with four different i-motif DNA sequences was thoroughly investigated by bio-layer interferometry (BLI) and circular dichroism (CD) spectroscopy. Surprisingly, our results show that IMC-48 is a very weak ligand of i-DNA as no quantifiable interaction or significant stabilization of i-motif structures could be observed, stimulating a quest for an alternative mechanism of its biological activity.

Chiral α-tertiary amines, a motif present in α,α-disubstituted α-amino acids, in a wide range of natural products, and many drugs and drug candidates, are important targets in organic chemistry. Among the possible strategies, 1,2-addition to chiral N-sulfinyl­ketimines is one of the best routes to form chiral α-tertiary amines with a high level of stereoselectivity. In this review, we focus first on the addition of organometallic reagents or other nucleophiles as enols or ylides to chiral N-sulfinylketimines. Then secondly we cover a selection of applications of these additions in the synthesis of valuable biologically active compounds.1 Introduction2 1,2-Addition Reaction Methodologies2.1 Organolithium Reagent Additions2.2 Grignard Additions2.3 Organozinc Reagent Additions2.4 Organoindium Reagent Additions2.5 Organoboron Reagent Additions2.6 Strecker Reactions2.7 Palladium-Catalyzed Reactions2.8 Enols, Enolates, and Other Deprotonated Reagent Additions2.9 Ylide Additions2.10 Heteroatom Nucleophiles2.11 Miscellaneous Reactions3 Applications to the Synthesis of Biologically Active Molecules4 Conclusions

Photoinduced Organic Reactions by Employing Pyrene Catalysts

The ligand N,N '-bis(2-amino-3,5-di-tert-butylphenyl)-2,2 '-diaminobiphenyl was synthesized and coordinated to copper. Complex 1(+) was structurally characterized, showing two deprotonated diiminobenzoquinone ligands coordinated to a single Cu(I) center. The paramagnetic complexes 1 and 1(2+) were generated and characterized by EPR and Vis-NIR spectroscopy. Complex 1 exhibits an isotropic resonance at g=2.00, which is reminiscent of Cu(I) diiminosemiquinone species. The dication 1(2+) exhibits a metal-based ground spin state and hence is described as a Cu(II) diiminobenzoquinone complex. Both 1 and 1(+) show a NIR band (954, 980 nm) of high intensity (>20 mM(-1) cm(-1)) assigned to ligand-based charge transfer transitions.

Strongly distorted copper salen complexes show a unique stability in four different redox states by CV. Copper phenoxyl radical complexes are structurally characterized. They promote the catalytic aerobic oxidation of 2-phenylethanol under air.

Chiral sulfinamides are very valuable, commercially available, and easy to handle chiral auxiliaries. One of the most interesting transformations that can be performed with a chiral sulfinamide is its condensation onto a ketone to form a chiral sulfinylketimine, followed by a reduction to obtain an α‐chiral primary amine. We review here all the methodologies developed around this condensation/reduction transformation. In the second part, we survey applications of these newly developed methodologies for the synthesis of valuable biologically active compounds, including multikilogram scale synthesis.

The sterically hindered bis(phenol)-dipyrrin ligands HLH3 and PhLH3 were reacted with 1 equiv of copper(II) under ambient conditions to produce the copper radical complexes [Cu(HL)] and [Cu(PhL)]. Their X-ray crystal structures show relatively short C-O bond distances (mean bond distances of 1.287 and 1.291 Å), reminiscent of mixed pyrrolyl-phenoxyl radical species. Complexes [Cu(HL)] and [Cu(PhL)] exhibit rich electronic spectra, with an intense near-IR (NIR) band (ε > 6 mM-1 cm-1) at 1346 and 1321 nm, respectively, assigned to a ligand-to-ligand charger-transfer transition. Both show a reversible oxidation wave ( E1/21,ox = 0.05 and 0.04 V), as well as a reversible reduction wave ( E1/21,red = -0.40 and -0.56 V versus ferrocenium/ferrocene, respectively). The cations ([Cu(HL)]+ and [Cu(PhL)]+) and anions ([Cu(HL)]- and [Cu(PhL)]-) were generated. They all display an axial ( S = 1/2) signal with a copper hyperfine structure in their electron paramagnetic resonance spectra, consistent with ligand-centered redox processes in both reduction and oxidation. Complex [Cu(HL)](SbF6) was cocrystallized with [Cu(HL)]. Oxidation is accompanied by a slight contraction of both the C-O bonds (mean bond distance of 1.280 Å) and the C-C bonds connecting the peripheral rings to the dipyrrin. The cations show vis-NIR bands of up to 1090 nm due to their quinoidal nature. The anions do not show a significant band above 700 nm, in agreement with their bis(phenolate)-dipyrrin character. The radical complexes efficiently catalyze the aerobic oxidation of benzyl alcohol, 1-phenylethanol, and unactivated 2-phenylethanol in basic conditions.

An unprecedented 7-membered ring cyclization of an enamide to a phenol through hypervalent iodine phenolic oxidation was discovered. In the process a molecule of solvent is incorporated on the cycle forming an unusual and stable hemi-aminal ether. (C) 2018 Elsevier Ltd. All rights reserved.

Condensation of compounds containing active methylene group with aromatic aldehyde (piperonal) in the presence of BaO on KF without a solvent under microwave irradiation is an efficient synthetic approach to methysticin and derivatives of kavalactones (4-methoxy-6-styryl-pyran-2-ones).

Three copper(II) complexes of the (R,R)-N,N'-bis(3,5-di-tert-butyl-2-aminobenzylidene)-1,2-diaminocyclohexane ligand, namely [Cu(N L)], [Cu(N LH)]+ and [Cu(N LH2 )]2+ , were prepared and structurally characterized. In [Cu(N LH2 )]2+ the copper ion lies in an octahedral geometry with the aniline groups coordinated in equatorial positions. In [Cu(N L)] the anilines are deprotonated (anilido moieties) and coordinated to an almost square-planar metal ion. Complex [Cu(N L)] displays two oxidation waves at E1/2ox, 1 =-0.14 V and E1/2ox, 2 =0.36 V vs. Fc+ /Fc in CH2 Cl2 . Complex [Cu(N LH2 )]2+ displays an irreversible oxidation wave at high potential (1.21 V), but shows a readily accessible and reversible metal-centered reduction at E1/2red =-0.67 V (CuII /CuI redox couple). Oxidation of [Cu(N L)] by AgSbF6 produces [Cu(N L)](SbF6 ), which was isolated as single crystals. X-ray structure analysis discloses a contraction of the coordination sphere by 0.05 Å upon oxidation, supporting a metal-centered process. Complex [Cu(N L)](SbF6 ) displays an intense NIR band at 1260 nm corresponding to an anilido-to-copper(III) charge transfer transition. This compound slowly evolves in CH2 Cl2 solution towards [Cu(N LH)](SbF6 ), which is a copper(II) complex comprised of both anilido and aniline groups coordinated to the metal center. The copper(III) complex [Cu(N L)](SbF6 ) is an efficient catalyst for benzyl alcohol oxidation, with 236 TON in 24 h at 298 K, without additives other than oxygen and a base.

CuII and CuIII complexes were synthesized from an anilinosalen ligand. A metal-centered single oxidation was ascertained by X-ray diffraction, which shows a contraction of the coordination sphere by around 0.05 Å. The CuIII complex exhibits an unprecedented NIR band, which arises from an anilido-to-copper charge transfer. This complex catalyzes the aerobic oxidation of benzyl alcohol under basic conditions very efficiently. It is in fact more active than galactose oxidase models based on CuII-phenoxyl salen complexes (valence tautomer), showing that the electronic structure is not a key factor in governing the reactivity. More information can be found in the Full Paper by F. Thomas et al. on page 13929.

A convenient green procedure have been proposed for the synthesis of 6-(2-arylvinyl)-4-hydroxy-3-(phenylsulfanyl)-2H-pyran-2-ones by condensation of 6-(arylvinyl)-4-hydroxy-2H-pyran-2-ones with S-phenyl benzenesulfonothioate in aqueous potassium hydroxide at room temperature.

The work undertaken resides in the development of new methods of synthesis respectful of the environment. A convenient synthesis of bis(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl) arylmethanes are obtained by condensation of triacetic acid lactone (4-hydroxy-6Methy1-2H-pyran-2-one) with aromatic aldehydes, in absence of the catalyst, without solvent by activation under microwave irradiation. This method has environmentally friendly advantages, short reaction time, high yields and easy preparation. We report here the synthesis of new heterocyclic compounds (dilactones) from TAL providing evidence for the particular reactivity of the position 3 of these compounds.