Synthesis of Highly Charged C3-Symmetrical Organic Molecule with a Fused Planar Core Structure

A new C3-symmetric molecule integrated with a number of interesting features, including three highly charged and flexible pyrrolidinium arms extending from a fused planar core structure, is synthesized.     

Efficient One-Step Synthesis of C 3-Symmetrical Benzenoid Compounds Mediated by SOCl2/EtOH

Abstract

An efficient one-step synthesis of branched functionalized benzenoid compounds from aryl methyl ketones mediated by SOCl₂/EtOH is described; some novel C ₃-symmetrical molecules were prepared with satisfactory yields. The method enjoys short reaction time and simple operation, and avoids use of organometallic reagents.     

Synthesis of New Chiral C2-Symmetrical Bis(oxazoline )Compounds

New chiral C2-symmetrical bis(oxazoline)compounds bearing one isobutyl-,secbutyl-benzyl- or isopropyl-substituent at the 4-position have been prepared and characterized.     

C2-Symmetrical Pyrrolidine Derivatives Chiral Auxiliaries in Radical Chemistry

Fumaramides 3b and 3c bearing the C₂-symmetrical pyrrolidine moieties (2R,5R)-2,5-bis(methoxymethyl)pyrrolidine ( 2b ) or 1,3:4,6-di-O-benzylidene-2,5-dideoxy-2,5-imino-L -idit ( 2c ), respectively, as a chiral auxiliary lead to high diastereoselectivities in radical reactions (‘tin method’;Scheme 1). Removal of the chiral auxiliaries affords the corresponding alkylated fumaric acids Scheme 2. Single-crystal X-ray structures of 3b and 3c support arguments that lead to the model of 1,4-stereoinduction.     

Asymmetric Diels-Alder Cycloadditions with C2-Symmetrical Chiral Carbamoylnitroso Dienophiles

The C₂-symmetrical chiral pyrrolidines 2 and 3 are of opposite helicity. The corresponding N-acylnitroso dienophiles 6 and 7 react in good yield with cyclohexadiene, leading thereby with excellent diastereoisomeric excess to the expected Diels-Alder cycloadducts (see Scheme). The [2.2.2] bicyclic moieties of the major diastereoisomers 9 and 11 proved to be of opposite configuration, as expected. Their configuration is best explained by assuming the acylnitroso dienophile to be in the s-cis conformation in the transition state, the approach of the diene being endo (see Fig.).     

Yellow Circularly Polarized Luminescence from C1-Symmetrical Copper(I) Complexes

The synthesis of chiral C₁-symmetrical copper(I) complexes supported by chiral carbene ligands is described. These complexes are yellow emitters with modest quantum yields. Circularly polarized luminescence (CPL) spectra show a polarized emission band with dissymmetry factors |g_lum|=1.2×10⁻³. These complexes are the first reported examples of molecular copper(I) complexes exhibiting circularly polarized luminescence. In contrast with most CPL-emitting molecules, which possess either helical or axial chirality, the results presented show that simple chiral architectures are suitable for CPL emission and unlock new synthetic possibilities.     

Synthesis and Potential Application of Novel C2-Symmetrical Bis（ferrocenyl） P2N Ligand

A novel chiral bis(ferrocenyl) P2N ligand 1 with C2-symmetry was synthesized through a four-step procedure from (R)-N,N-dimethyl-l-ferrocenylethylamine. In a model reaction of Pdcatalyzed allylic alkylation of 1,3-diphenylprop-2-enyl acetate 6 with dimethyl malonate, good enantioselectivity (86% e.e.) was obtained.     

Highly diastereoselective and enantioselective synthesis of enantiopure C2-Symmetrical vicinal diamines by reductive homocoupling of chiral N-tert-butanesulfinyl imines

[reaction: see text] An efficient and straightforward method for the preparation of highly enantiomerically enriched C2-symmetrical vicinal diamines by the reductive homocoupling of aromatic N-tert-butanesulfinyl imines in the presence of SmI2 and HMPA was developed. It gives access to a variety of enantiopure C2-symmetrical 1,2-diamines in a very mild and practical way.     

From Cycloolefins to Linear C2-Symmetrical 1,4-Diamino-2,3-diol Building Blocks—Peptide Mimetics,Biocatalysis, and Pinacol Coupling of α-Amino Aldehydes

Technical olefins and azodicarbonic ester are the starting materials for C₂-symmetrical C₁₆ and C₁₂ 1,4-diamino-2,3-diol building blocks (see structure), which are of interest for a variable access to potentially bioactive compounds (peptide mimetics, enzyme inhibitors). MOM = methoxymethyl.     

A Comparative Study of the Cyclic Chlorophosphites with C2-Symmetrical Organic Fragments as the Reagents for Enantiomeric Composition Control of the Chiral Alcholos

Abstract

The ³¹P NMR method is intensively used for enantiomeric composition control during the last years [1]. Among all other derivatizing agents the C₂-symmetrical ones have some advantages.     

A Comparative Study of the Cyclic Chlorophosphites with C2-Symmetrical Organic Fragments as the Reagents for Enantiomeric Composition Control of the Chiral Alcohols

Abstract

The ³¹P NMR method is intensively used for enantiomeric composition control during the last years [I]. Among all other derivatizing agents the C2-symmetrical ones have some advantages.     

Two New Co(II)-Cluster-Based Coordination Polymers Based on the C<Subscript>3</Subscript>-Symmetrical Organic Ligand: Synthesis,Crystal Structures and Anti-Liver Cancer Activity

In this work, two new Co(II)-cluster-based coordination polymers have been obtained via a one pot solvothermal reaction of Co(NO₃)₂·6H₂O with two similar C₃-symmetrical polycarboxylic acid organic ligands with or without auxiliary organic ligands, which reveal different framework dimensionality. The compound 1 with the chemical formula of [Co₃(NTB)₂(bpy)₂](DMA)₂ (byp?=?4,4′-bipyridine, H₃NTB?=?4,4′,4′′-nitrilotribenzoic acid) is constructed from the linear Co3 cluster which is further extended via the rigid NTB^3? and bpy ligands to afford a three-dimensional framework, while complex 2 with the formula of [Co₂(HTPA)₂(H₂O)₂](DMA)₂ (H₃TPA?=?tris((4-carboxyl)phenylduryl)amine) is built from the binuclear Co(II)-cluster that shows a two-dimensional framework due to partly deprotonation of the carboxylic groups of the H₃TPA ligand. Furthermore, the in vitro anticancer activity was then evaluated against human liver cancer cell lines HepG2 via the MTT assay.     

Theoretical study of highly excited Σ and Π states of NaLi and experimental observation of the interacting 5Σ and 6Σ states

Theoretical multireference configuration interaction (MRDCI) calculations on the excited ¹Σ⁺ and ¹Π states of NaLi are presented. They improve the results of a previous study by two of the present authors, resolve some differences with other theoretical results and lead to overall good agreement with experimental observations. To extend the experimental data base of electronic states in NaLi, a previously unknown ¹Σ⁺ state is investigated by polarisation labelling spectroscopy. Comparison with accompanying and previous theoretical calculations leads to a conclusion that the observed system consists of two band systems switching smoothly from one adiabatic state to the other and allows assignment of the bands as 5¹Σ⁺ ← X¹Σ⁺ in the lower energy part and to 6¹Σ⁺ ← X¹Σ⁺ for higher energies.     

Energies and radial couplings for the Σ and Σ states of the NaHe quasimolecule

We present the energies and radial couplings for the five ¹Σ and four ³Σ states of lowest energy of the NaHe⁺ quasimolecule, with a precision which is sufficient to treat Na/He⁺ collisions. The characteristics of energies and couplings are studied in detail with the aid of qualitative orbital and state-correlation diagrams.     

Reactions of N2(A3Σ)

N₂(A³Σ), the lowest electronically excited state of N₂, has a long and distinguished history due to its role in nitrogen discharges and the nitrogen afterglow. Recently, the production of N₂(A) via photolysis and chemiluminescent reactions has been newly explored, and new facets of its reactivity have been uncovered. N₂(A) is unusual, in that its deactivation probability in collision with small molecules spans many orders of magnitude, and is frequently strongly dependent on the vibrational content of N₂(A). This behavior and the observed product channels can be understood in terms of a simple model for the energy transfer process. Brief comparison with reactions of related species is made.