Synthesis of a new estradiol-iron metalloporphyrin conjugate used to build up a new hybrid biocatalyst for selective oxidations by the ‘Trojan horse’ strategy

The synthesis of a new cationic iron metalloporphyrin-estradiol conjugate is reported. After a study of its association with the anti-estradiol antibody 7A3 by UV-visible spectroscopy, the influence of the antibody on the sulfoxidation of thioanisole by H₂O₂ catalyzed by the iron-metalloporphyrin has been investigated.     

Two Stereoinduction Events in One C−H Activation Step: A Route towards Terphenyl Ligands with Two Atropisomeric Axes

Herein we disclose the synthesis of original chiral scaffolds—ortho‐orientated terphenyls presenting two atropisomeric Ar–Ar axes. These unusual structures were built up by using the C?H activation approach, and remarkably, both chiral axes were controlled with excellent stereoselectivity in a single transformation. During the reaction, not only does atroposelective functionalization of a biaryl precursor occur to establish one stereogenic axis, but an unprecedented atropo‐stereoselective C?H arylation also takes place to generate the second stereogenic element. These enantiomerically pure ortho‐terphenyls show an original tridimensional structure and thus constitute a unique foundation for building up a library of enantiomerically pure bidentate ligands, such as the new ligands S/N‐Biax and diphosphine BiaxPhos.     

Effect of light on calcium transport in bull sperm cells.

The effect of light on calcium transport was studied. Bull sperm cells were irradiated with an He-Ne (630 mm) laser and a 780 nm diode laser at various energy doses, and 45Ca2+ uptake was measured by the filtration technique. It was found that there is an accelerated Ca2+ transport in the irradiated cells, which means that laser light can stimulate Ca2+ exchange through the cell membrane. This may cause transient changes in the cytoplasmic Ca2+ concentration which, in spermatozoa, has a regulatory role in control of motility and acrosome reaction, and in other cells can trigger mitosis.     

Synthesis of methylene butyrolactone polymers from itaconic acid

Herein, we report the transformation of β‐monomethyl itaconate, an inexpensive and biorenewable alternative to petroleum feedstocks, to the high‐value monomer α‐methylene‐γ,γ‐dimethyl‐γ‐butyrolactone (Me₂MBL) through a selective addition strategy. This strategy is also applied to the synthesis of α‐methylene‐γ‐butyrolactone (MBL, tulipalin A), a monomer that can be polymerized to give materials with desirable properties (high decomposition temperature, glass transition temperature, and refractive index). Subsequent polymerization of both Me₂MBL and MBL through reversible addition‐fragmentation chain‐transfer polymerization generates well‐defined poly(Me₂MBL) and poly(MBL) (PMBL). Physical characterization of poly(Me₂MBL) shows good physical properties comparable with known PMBL materials. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2730–2737     

Merging metathesis and photochemical Csp3-H activation: Access to masked β-formyl hexanolides and their rearrangement to furofuranones

β-Masked formyl hexanolides were prepared by a three-step sequence including esterification of homoallylic alcohols, ring-closing metathesis and the photochemically induced addition of dioxanyl radical. When treated under oxidative conditions, the adducts underwent cleavage of the ketal group leading after rearrangement to parent furofuranones, structures found in some biological active compounds.     

One Amine–3 Tasks: Reductive Coupling of Imines with Olefins in Batch and Flow

Owing to their wide range of biological properties, γ-aminobutyric acid derivatives (GABA) have been extensively studied and found noteworthy industrial applications. However, atom-economical and efficient processes for their production are scarce and would greatly benefit from further investigations. Herein, we demonstrate that an iridium-based photocatalyst promotes the direct reductive cross-coupling of imines with olefins upon irradiation with visible light to give GABA derivatives in good yields and selectivities. We also stress the enabling triple role of tributylamine additive in this process, discuss the advantages of strategies based on proton-coupled electron transfer (PCET) and demonstrate the scale-up of this reaction in continuous flow.     

Chiral Supramolecular Nanotubes of Single-Chain Magnets

We report a single-chain magnet (SCM) made of a terbium(III) building block and a nitronyl-nitroxide radical (NIT) functionalized with an aliphatic chain. This substitution is targeted to induce a long-range distortion of the polymeric chain and accordingly it gives rise to chains that are curled with almost 20 nm helical pitch. They self-organize as a chiral tubular superstructure made of 11 chains wound around each other. The supramolecular tubes have a 4.5 nm internal diameter. Overall, this forms a porous chiral network with almost 44 % porosity. Ab initio calculations highlight that each Tb^III ion possesses high magnetic anisotropy. Indeed, notwithstanding the supramolecular arrangement each chain behaves as a SCM. Magnetic relaxation with both finite and infinite-size regimes is observed and confirms the validity of the Ising approximation. This is associated with quite strong coercive field and magnetic remanence (H_c=2400 Oe M_R=2.09 μ_B at 0.5 K) for this class of compounds.