Sequential Deprotonation–Alkylation of Binaphthyloxy-Substituted Phosphonochalcogenoates: Chiral Tri- and Tetrasubstituted Carbon Centers Adjacent to a Phosphorus Atom

Sequential deprotonation and alkylation of 1,1′-binaphthyloxy-substituted phosphonoselenoates and phosphonates resulted in the diastereoselective formation of chiral tri- and tetrasubstituted carbon centers adjacent to a phosphorus atom

Sequential Deprotonation–Alkylation of Binaphthyloxy-Substituted Phosphonochalcogenoates: Chiral Tri- and Tetrasubstituted Carbon Centers Adjacent to a Phosphorus Atom

Sequential deprotonation and alkylation of 1,1′-binaphthyloxy-substituted phosphonoselenoates and phosphonates resulted in the diastereoselective formation of chiral tri- and tetrasubstituted carbon centers adjacent to a phosphorus atom

α‑Hydroxy and α‑Oxo Selenoamides: Synthesis via Nucleophilic Selenocarbamoylation of Carbonyl Compounds and Characterization

Carbonyl compounds were added to selenocarbamoyllithiums to generate α-hydroxy and α-oxo selenoamides. Their conformations were determined by X-ray analyses. These compounds adopted conformations that were almost identical to those of ordinary amides. Unlike the consistency of the chemical shifts of the CSe groups of the selenoamides in ¹³C NMR spectra and the ¹<i>J</i> coupling constants of the CSe groups, the substituents far from the selenium atom influenced the chemical shifts in ⁷⁷Se NMR

Reaction of Selenoamide Dianions with Thio- and Selenoformamides Leading to the Formation of 5‑Aminoselenazoles: Photophysical and Electrochemical Properties

5-Amino-2-selenazolines were synthesized by reacting selenoamide dianions generated from secondary selenoamides and BuLi with tertiary thio- and selenoformamides followed by treatment with iodine. The resulting 5-amino-2-selenazolines were further oxidized with iodine to give 5-aminoselenazoles in moderate to good yields. The general tendencies in the ⁷⁷Se NMR spectra of the starting selenoamides, 5-amino-2-selenazolines, and 5-aminoselenazoles were determined. The chemical shifts of these compounds were highly influenced by the skeletons involving the selenium atom as well as the substituents on the carbon atoms of each skeleton. The molecular structures of 5-aminoselenazoles were clarified by X-ray analyses, and their electronic structures were elucidated by DFT calculations. Finally, UV–vis and fluorescence spectroscopy and cyclic voltammetry (CV) of 5-aminoselenazoles were performed, and their properties are discussed in relation to the substituents on the selenazole rings

Harnessing Chalcogen-bonding Interactions To Establish Conformational Control in Dirhodium(II) Paddlewheel Complexes

Novel well-defined D2-symmetric dirhodium(II) carboxylate complexes that bear axially chiral binaphthothiophene delta-amino acid derivatives have been developed. Conformational control was achieved through chalcogen-bonding interactions between sulfur and oxygen atoms in each ligand, providing well-defined and uniform asymmetric environments around the catalytically active Rh(II) centers. These structural properties render such complexes excellent catalysts for the inside-type asymmetric intramolecular C–H insertion into alpha-aryl-alpha-diazoacetates to yield a variety of cis- alpha, beta-diaryl gamma-lactones, as well as the corresponding trans-isomers through epimerization, in high diastereo- and enantioselectivities. Short total syntheses of the naturally occurring gamma-lactones cinnamomumolide, cinncassin A7, and cinnamomulactone were also accomplished using this conformationally controlled catalyst.<br /

One-Pot Preparation of (NH)-Phenanthridinones and Amide-Functionalized [7]Helicene-like Molecules from Biaryl Dicar-boxylic Acids

A one-pot transformation of biaryl dicarboxylic acids to (NH)-phenanthridinone derivatives based on a Curtius rearrangement and subsequent basic hydrolysis was developed. This method is also applicable for the preparation of optically active amide-functionalized [7]helicene-like molecules. Furthermore, aza[5]helicene derivatives with a phosphate moiety were isolated as a product of the Curtius rearrangement step in the case of substrates that bear chalcogen atoms. The stereostructures of these products, revealed by X-ray diffraction analysis, suggested that chalcogen-bonding and pnictogen-bonding interactions might contribute to their stabilization. The configurational stability of the helicene-like molecules and their chiroptical properties were further investigated

Synthesis and Photophysical Properties of 5‑<i>N</i>‑Arylamino-4-methylthiazoles Obtained from Direct C–H Arylations and Buchwald–Hartwig Aminations of 4‑Methylthiazole

5-<i>N</i>-Arylamino-4-methylthiazoles were synthesized from commercially available 4-methylthiazole in three consecutive steps: (i) direct Pd-catalyzed C–H arylations of the thiazole, (ii) bromination, and (iii) Pd-catalyzed Buchwald–Hartwig aminations. The resulting thiazoles showed the longest-wavelength absorption maxima at 338–432 nm, and luminescence was observed at 455–726 nm, whereby the latter depends predominantly on the substituents at the 2-position of the thiazole core. The introduction of electron-accepting groups, in particular a nitro group, induced substantial bathochromic shifts of the fluorescence. Thiazoles containing a 3,5-bis­(trifluoromethyl)­phenyl group at the 2-position exhibited purple to blue emission in the solid state. The energy levels of the frontier molecular orbitals and the Kohn–Sham plots of the 5-<i>N</i>-arylamino-4-methylthiazoles were obtained from DFT calculations at the B3LYP/6-31+G­(d,p) level of theory