PREPARATION A SERIES OF ATROPISOMERIC BIPY-DIOXIDES BY OXIDATIVE COUPLING AND THEIR APPLICATION IN ASYMMETRIC CATALYSIS

The authors thank the Russian Science Foundation for Grant No. 18-73-10156

Морфология спор Parahemionitis arifolia (Cheilanthoideae, Pteridaceae)

A study of spores of the single species of the genus Parahemionitis Panigrahi was performed using the method of scanning electronic microscopy (SEM). Spores of Parahemionitis arifolia (Burm. f.) Panigrahi are tetrahedral trilete, roundish-triangular in polar position, with micro-wrinkled exospore and sculptured perispore. Sculpture of perispore is cristate-reticulate, cristae are quite regularly distributed and form reticulum with small mostly closed polygonal luminae of different shape. Laesura arms are often obscured by numerous cristae. Size of spores is 53–63 × 40–42 μm. Spores of P. arifolia are similar in perispore sculpture with those of species of some cheilanthoid ferns

Asymmetric Propargylation of Aldehydes Catalyzed by New Chiral Lewis Bases

The authors thank the Russian Science Foundation for Grant № 18-73-10156

Stereoselective Synthesis of Atropisomeric Bipyridine N,N′-Dioxides by Oxidative Coupling

Bipyridine N,N′-dioxide is a structural fragment found in many bioactive compounds. Furthermore, chiral analogues secured their place as powerful Lewis base catalysts. The scope of the existing methods for the synthesis of atropisomeric bipyridine N,N′-dioxides is limited. Herein, we present a practical, highly chemo- and stereoselective method for oxidative dimerization of chiral pyridine N-oxides using O2 as a terminal oxidant. A series of 13 axially chiral bipyridine N,N′-dioxides were synthesized in up to 75% yield. © 2019 American Chemical Society

Data on spore morphology of Cerosora microphylla (Anogramma microphylla) (Pteridaceae)

We used the method of scanning electron microscopy (SEM) to study the representatives of the genus Anogramma from South-West Asia and the Himalayas. To confirm the presence of Cerosora microphylla (Hook.) R.M. Tryon in China (hence, the absence of Anogramma microphylla (Hook.) Diels), we revealed the features of external morphology of spores that are not inherent in representatives of the genus Anogramma: absence of an equatorial ridge, roundish-triangular shape of the spores in the proximal-polar and distal-polar positions; absence of roller-like bulges extending upward in the form of ridges along the contour of the distal side of the spore; roller-like folds extending upward in the form of ridges both on the proximal and distal sides of the spore. In addition, one feature revealed for C. microphylla – spherical tubercles between the proximal and distal roller-like folds located along the spore equator – indicates its high species-specificity. We used the method of scanning electron microscopy (SEM) to study the representatives of the genus Anogramma from South-West Asia and the Himalayas. To confirm the presence of Cerosora microphylla (Hook.) R.M. Tryon in China (hence, the absence of Anogramma microphylla (Hook.) Diels), we revealed the features of external morphology of spores that are not inherent in representatives of the genus Anogramma: absence of an equatorial ridge, roundish-triangular shape of the spores in the proximal-polar and distal-polar positions; absence of roller-like bulges extending upward in the form of ridges along the contour of the distal side of the spore; roller-like folds extending upward in the form of ridges both on the proximal and distal sides of the spore. In addition, one feature revealed for C. microphylla – spherical tubercles between the proximal and distal roller-like folds located along the spore equator – indicates its high species-specificity.

Enantioselective propargylation of aldehydes catalyzed by new chiral Lewis bases

In this work we’ve designed a series of new chiral Lewis Bases and show their excellent catalytic ability in the reaction of asymmetric propargylation of aromatic and α-unsaturated aldehydes.The authors thank the Russian Science Foundation for Grant 18-73-10156

Dehydration of Amides to Nitriles

The authors thank Russian Science Foundation for grant № 18-73-10156

Electronic energy band parameters of CuInSe2 : Landau levels in magnetotransmission spectra

Magnetotransmission (MT) at magnetic fields up to 29 T was used to study the electronic structure of CuInSe2 in thin polycrystalline films. The zero field absorption spectra exhibited resolved A, B, and C free excitons. Quantum oscillations, due to diamagnetic excitons comprising electrons and holes from Landau levels quantized in the conduction and valence band, respectively, appeared in the MT spectra at fields over 5 T. Spectral energies of Landau levels and binding energies of the corresponding diamagnetic excitons, theoretically calculated assuming a quasicubic approximation of the CuInSe2 tetragonal lattice structure, helped to identify the character of the experimentally observed diamagnetic excitons. Spectral energies of diamagnetic excitons in the MT spectra with different circular polarizations were used to determine the electron and light hole effective masses, whereas heavy hole masses as well as the γ and γ1 Luttinger parameters, Ep Kane energy, and F parameter of the influence of remote bands, as well as their polaron values, were calculated using the Luttinger theory

New Axially Chiral Bipyridines and Their Application in Asymmetric Catalysis for Total Synthesis

The authors thank the Russian Science Foundation for Grant 18-73-10156