Convexity conditions for the space of regular operators

Positivity - In this article we study the following natural questions: When is the quasi-Banach lattice of regular linear operators or homogeneous polynomials between quasi-Banach lattices...     

Asymmetric Synthesis of Perfluoroalkylated α-Amino Acids through Generated Radicals Using a Chiral Ni(II) Complex

Perfluoroalkylated α-amino acids (PFAAs) are a unique class of compounds for biochemistry and pharmaceutical science. In this context, we report the successful intermolecular coupling of the Belokon’s chiral dehydroalanine Ni(II) complex with a variety of perfluoroalkyl iodides. A 4-cyanopyridine/B₂Pin₂ catalytic system generates perfluoroalkyl radicals, which after trapping by the ligand sphere of a chiral Ni(II) complex provide the diastereomeric complexes with up to >20 : 1 dr (seven examples). The obtained major (S,S)-diastereomers were easily isolated by simple silica column chromatography in 33–54 % yields. The perfluoroalkylated α-AA was subsequently released from the obtained Ni(II) complex through aqueous HCl treatment. The chiral auxiliary ligand ((S)-BPB=(S)-2-(N-benzylprolyl)aminobenzophenone) can be easily recycled after the acidic complex decomposition and reused for the synthesis of the starting dehydroalanine Ni(II) complex.     

Phytochemistry,Bioactivities and Traditional Uses of Michelia × alba

Michelia × alba (M. alba) is a flowering tree best known for its essential oil, which has long been used as a fragrance ingredient for perfume and cosmetics. In addition, the plant has been used in traditional medicine in Asia and dates back hundreds of years. To date, there is a limited number of publications on the bioactivities of M. alba, which focused on its tyrosinase inhibition, antimicrobial, antidiabetic, anti-inflammatory, and antioxidant activities. Nevertheless, M. alba may have additional unexplored bioactivities associated with its bioactive compounds such as linalool (72.8% in flower oil and 80.1% in leaf oil), α-terpineol (6.04% flower oil), phenylethyl alcohol (2.58% flower oil), β-pinene (2.39% flower oil), and geraniol (1.23% flower oil). Notably, these compounds have previously been reported to exhibit therapeutic activities such as anti-cancer, anti-inflammation, anti-depression, anti-ulcer, anti-hypertriglyceridemia, and anti-hypertensive activities. In this review paper, we examine and discuss the scientific evidence on the phytochemistry, bioactivities, and traditional uses of M. alba. Here, we report a total of 168 M. alba biological compounds and highlight the therapeutic potential of its key bioactive compounds. This review may provide insights into the therapeutic potential of M. alba and its biologically active components for the prevention and treatment of diseases and management of human health and wellness.     

Nickel-coordinated chiral enols and Michael addition intermediate stabilized by the Ni–C bond

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Four hydroxyls are better than two. The use of a chiral lithium salt of 3,3′-bis-methanol-2,2′-binaphthol as a multifunctional catalyst of enantioselective Michael addition reactions

The catalytic performance of the Li salt of (S)- or (R)-3,3′-bis[bis-(phenyl)hydroxymethyl]-2,2′-dihydroxy-dinaphthalene-1,1′ (BIMBOL) in asymmetric Michael additions of malonic acid derivatives and toluedine has been studied. Nitrostyrene and cyclohex-2-enone were chosen as Michael acceptors. Efficient asymmetric C-C and C-N bond formations with ee’s of up to 95% at room temperature were observed. A transition state model of the malonic ester addition to cyclohex-2-enone has been proposed based on the molecular structure of the acetone solvate of BIMBOL. The impact of the catalyst self-association on its performance is also discussed.     

Bis-TADDOLs as bifunctional organocatalysts for trifluoromethylation of aldehydes and ring-opening of cyclohexene oxide with p-toluidine

A set of bis-TADDOLs, in which two TADDOL moieties are connected by different linkers, have been prepared. A great dependence of the catalytic activities of the bis-TADDOLs on the distance between the TADDOL moieties was found by the addition of trifluoromethyltrimethylsilane to benzaldehyde and ring-opening of cyclohexene oxide with or without alkali metal salts added.