Stereoselective Synthesis of Spiro-α-methylene-γ-lactams via Chiral Quaternary 3-Aminooxindole Adducts Accessed by Zn-Mediated Allylation of Sulfinyl Ketimines

Synthesis ◽  
2020 ◽  
Vol 52 (17) ◽  
pp. 2551-2562 ◽  
Author(s):  
Ravi P. Singh ◽  
V. U. Bhaskara Rao ◽  
Shashank Singh ◽  
Krishna N. Tripathi
Keyword(s):  
Single Crystal ◽  
Structure Analysis ◽  
Efficient Method ◽  
Good Yield ◽  
Stereoselective Synthesis ◽  
High Selectivity ◽  
X Ray ◽  
Relative Stereochemistry ◽  
Very High

An efficient method for the stereoselective synthesis of α-methylene-γ-lactams via quaternary 3-aminooxindoles with very high selectivity (up to 98% ee) is described. The methodology leads to the construction of sterically congested chiral quaternary 3-aminooxindole adducts in good yield and with moderate to excellent diastereoselectivity (dr up to 95:5). The relative stereochemistry of the chiral quaternary 3-aminooxindoles adduct and the spiro-α-methylene-γ-lactam was confirmed to be syn by single-crystal X-ray structure analysis. Furthermore, the α-methylene-γ-lactam was successfully transformed into a range of chiral synthons.

Stereoselective Synthesis of Multifunctionalized Nitrones via Conjugate Addition Between α-Halogeno Hydrazones and Nitroso Compounds

Synlett ◽  
2021 ◽  
Author(s):  
Hong-Wu Zhao ◽  
Xiao-Fan Bi ◽  
Hai-Liang Pang ◽  
Zhe Tang ◽  
Heng Zhang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Structure Analysis ◽  
Chemical Structure ◽  
Stereoselective Synthesis ◽  
Conjugate Addition ◽  
Crystal Structure Analysis ◽  
Nitroso Compounds ◽  
X Ray ◽  
Single Crystal Structure Analysis

In the presence of Na2CO3, the conjugate addition between α-halogeno hydrazones and nitroso compounds proceeded readily, thus delivering multifunctionalized nitrones in the reasonable chemical yields with excellent strereoselectivities. The chemical structure and stereochemical configuration of title chemical entities were unambiguously identified by an X-ray single crystal structure analysis.

How the Magnetic Field Impacts the Chiroptical Activities of Helical Copper Enantiomers

2021 ◽  
Author(s):  
jialu wu ◽  
Bo Li ◽  
Hong Wang ◽  
Ying Zhen Lai ◽  
Yue Ye ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solid State ◽  
Thermogravimetric Analysis ◽  
Single Crystal ◽  
Structure Analysis ◽  
Chiral Ligands ◽  
X Ray ◽  
The Magnetic Field

A pair of enantiomers {[Cu(L-pro)(L-tyr)]·2H2O}n (L-1) and {[Cu(D-pro)(D-tyr)]·2H2O}n (D-1) based on the chiral ligands L/D-proline and L/D-tyrosine were synthesized and investigated by single-crystal X-ray structure analysis, IR, thermogravimetric analysis, solid-state...

Eine effiziente Synthesemethode für DiarylallenyIiden(pentacarbonyl)chrom- und -wolfram-Komplexe -Kristallstruktur von (CO)5Cr=C=C=CPh2 / An efficient Synthesis of Diarylallenylidene Pentacarbonyl Chromium and Tungsten Complexes - Crystal Structure of (CO)5Cr=C=C=CPh2

1994 ◽  
Vol 49 (9) ◽  
pp. 1207-1214 ◽  
Author(s):  
Helmut Fischer ◽  
David Reindl ◽  
Gerhard Roth
Keyword(s):  
Crystal Structure ◽  
Structure Analysis ◽  
Good Yield ◽  
Efficient Synthesis ◽  
X Ray ◽  
Tungsten Complexes ◽  
And Tungsten

An efficient synthesis of diarylallenylidene pentacarbonyl chromium and tungsten com­plexes is presented. Irradiation of M(CO)6 in THF affords (CO)sM[THF], Substitution of the THF ligand by diarylpropargylalcoholate and subsequent desoxygenation with COCF gives the title compounds in good yield. (The structure of diphenylallenylidene pentacarbonyl chromium has been determined by X-ray structure analysis

scholarly journals Arene Ruthenium Metalla-Assemblies with Anthracene Moieties for PDT Applications

Inorganics ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 97 ◽  
Author(s):  
Marie Gaschard ◽  
Farzaneh Nehzat ◽  
Thomas Cheminel ◽  
Bruno Therrien
Keyword(s):  
Molecular Structure ◽  
Single Crystal ◽  
General Formula ◽  
Structure Analysis ◽  
White Light ◽  
Light Irradiation ◽  
Synthesis And Characterization ◽  
X Ray

The synthesis and characterization of three metalla-rectangles of the general formula [Ru4(η6-p-cymene)4(μ4-clip)2(μ2-Lanthr)2][CF3SO3]4 (Lanthr: 9,10-bis(3,3’-ethynylpyridyl) anthracene; clip = oxa: oxalato; dobq: 2,5-dioxido-1,4-benzoquinonato; donq: 5,8-dioxido-1,4-naphthoquinonato) are presented. The molecular structure of the metalla-rectangle [Ru4(η6-p-cymene)4(μ4-oxa)2(μ2-Lanthr)2]4+ has been confirmed by the single-crystal X-ray structure analysis of [Ru4(η6-p-cymene)4(μ4-oxa)2(μ2-Lanthr)2][CF3SO3]4 · 4 acetone (A2 · 4 acetone), thus showing the anthracene moieties to be available for reaction with oxygen. While the formation of the endoperoxide form of Lanthr was observed in solution upon white light irradiation, the same reaction does not occur when Lanthr is part of the metalla-assemblies.

scholarly journals A Covalent Organic Cage Compound Acting as a Supramolecular Shadow Mask for the Regioselective Functionalization of C60

2020 ◽  
Author(s):  
Viktoria Leonhardt ◽  
Stefanie Fimmel ◽  
Ana-Maria Krause ◽  
Florian Beuerle
Keyword(s):  
Mass Spectrometry ◽  
Single Crystal ◽  
High Selectivity ◽  
Shadow Mask ◽  
X Ray Diffraction ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Cage Compound ◽  
Vis Spectroscopy ◽  
Regioselective Functionalization

<div><div><div><p>A trigonal-bipyramidal covalent organic cage compound serves as an efficient host to form stable 1:1-complexes with C60 and C70. Fullerene encapsulation has been comprehensively studied by NMR and UV/Vis spectroscopy, mass spectrometry as well as single-crystal X-ray diffraction. Exohedral functionalization of encapsulated C60 via threefold Prato reaction revealed high selectivity for the symmetry-matched all-trans-3 addition pattern.</p></div></div></div>

scholarly journals Stereoselective synthesis and transformation of pinane-based 2-amino-1,3-diols

2021 ◽  
Vol 17 ◽  
pp. 983-990
Author(s):  
Ákos Bajtel ◽  
Mounir Raji ◽  
Matti Haukka ◽  
Ferenc Fülöp ◽  
Zsolt Szakonyi
Keyword(s):  
Alkaline Hydrolysis ◽  
Stereoselective Synthesis ◽  
2D Nmr ◽  
Ring Closure ◽  
Spectroscopic Techniques ◽  
Reductive Alkylation ◽  
X Ray ◽  
Relative Stereochemistry ◽  
Hydrolysis Of

A library of pinane-based 2-amino-1,3-diols was synthesised in a stereoselective manner. Isopinocarveol prepared from (−)-α-pinene was converted into condensed oxazolidin-2-one in two steps by carbamate formation followed by a stereoselective aminohydroxylation process. The relative stereochemistry of the pinane-fused oxazolidin-2-one was determined by 2D NMR and X-ray spectroscopic techniques. The regioisomeric spiro-oxazolidin-2-one was prepared in a similar way starting from the commercially available (1R)-(−)-myrtenol (10). The reduction or alkaline hydrolysis of the oxazolidines, followed by reductive alkylation resulted in primary and secondary 2-amino-1,3-diols, which underwent a regioselective ring closure with formaldehyde or benzaldehyde delivering pinane-condensed oxazolidines. During the preparation of 2-phenyliminooxazolidine, an interesting ring–ring tautomerism was observed in CDCl3.

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