scholarly journals First Total Synthesis of Varioxiranol A

Molecules ◽  
2019 ◽  
Vol 24 (5) ◽  
pp. 862 ◽  
Author(s):  
Angelika Lásiková ◽  
Jana Doháňošová ◽  
Mária Štiblariková ◽  
Martin Parák ◽  
Ján Moncol ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Single Crystal ◽  
Absolute Configuration ◽  
Coupling Reaction ◽  
X Ray ◽  
Synthetic Strategy

The paper describes the first total synthesis of natural varioxiranol A by chiral pool approach and confirmation of its absolute configuration by single-crystal X-ray analysis. The target varioxiranol A and its 4-epimer were obtained after 10 steps from single and available chiral source 1,2-O-isopropylidene-d-glyceraldehyde in an overall yield of 10% and 6%, respectively. A synthetic strategy based on the Julia–Kocieński coupling reaction between aromatic sulfone and corresponding aldose derivative makes it possible to prepare other interesting polyketide derivatives (varioxiranols B-G, varioxirane, varioxiranediols).

A Chemoenzymatic Total Synthesis of the Undecenolide ( - )-Cladospolide C

2005 ◽  
Vol 58 (7) ◽  
pp. 511 ◽  
Author(s):  
Martin G. Banwell ◽  
David T. J. Loong ◽  
Anthony C. Willis
Keyword(s):  
Total Synthesis ◽  
Single Crystal ◽  
Natural Product ◽  
Absolute Configuration ◽  
Starting Material ◽  
Unsaturated Ester ◽  
Ring Closing Metathesis ◽  
X Ray ◽  
Key Steps ◽  
First Time

The (−)-enantiomer, ent-3, of the natural product (+)-cladospolide C (3) has been prepared for the first time using the monochiral cis-1,2-dihydrocatechol 5 as starting material. Key steps include coupling of the derived acid 6 with the enzymatically generated (S)-(+)-4-penten-2-ol (7) and ring-closing metathesis (RCM) of the resultant doubly unsaturated ester 8 to give lactone 9. The structure of this last compound has been confirmed by single-crystal X-ray analysis. This work has established that the absolute configuration of (+)-cladospolide C has been correctly assigned and is as illustrated in structure 3.

scholarly journals Stereoselective Convergent Synthesis of Carbon Skeleton of Cotylenin A Aglycone

Synthesis ◽  
2021 ◽  
Author(s):  
Kazuyuki Sugita ◽  
Motoi Kuwabara ◽  
Ami Matsuo ◽  
Shogo Kamo ◽  
Akinobu Matsuzawa
Keyword(s):  
Single Crystal ◽  
Aldol Reaction ◽  
Coupling Reaction ◽  
Carbon Skeleton ◽  
Convergent Synthesis ◽  
X Ray ◽  
Related Compounds

AbstractIn this paper, the synthesis of the carbon skeleton of cotylenin A aglycone is described. The key reactions, including an intramolecular aldol reaction, an aldol coupling reaction, and a ring-closing meta­thesis, allow for the effective and stereoselective access to the carbon skeleton of cotylenin A aglycone. The stereochemistry was confirmed by single-crystal X-ray crystallographic analyses of related compounds.

Crystal structures of (S)- and (R,S)-2,2′-bipyridine-3,3′-dicarboxylic acid 1,1′-dioxides and of their barium salts: absolute configuration and molecular distortion enforced by supramolecular self-assembly

1997 ◽  
Vol 212 (3) ◽  
Author(s):  
P. Vojtíšek ◽  
I. Císařová ◽  
J. Podlaha ◽  
Z. Žák ◽  
S. Böhm ◽  
...  
Keyword(s):  
Single Crystal ◽  
Dicarboxylic Acid ◽  
Crystal Structures ◽  
Absolute Configuration ◽  
Self Assembly ◽  
Barium Salt ◽  
X Ray Diffraction ◽  
X Ray

AbstractCrystal structures of the title compounds were determined by single crystal X-ray diffraction. Absolute configuration of the barium salt of (+)-(

scholarly journals Some experimental aspects of absolute configuration determination using single crystal X-ray diffraction

2017 ◽  
Vol 28 (10) ◽  
pp. 1330-1336 ◽  
Author(s):  
Amber L. Thompson ◽  
Sarah F. Jenkinson ◽  
George W.J. Fleet
Keyword(s):  
Single Crystal ◽  
Absolute Configuration ◽  
X Ray Diffraction ◽  
X Ray

First total synthesis of (±)-myltayl-4(12)-ene and single-crystal X-ray structure of exo-12-normyltaylan-4-yl 4-nitrobenzoate

1994 ◽  
Vol 0 (19) ◽  
pp. 2259-2260 ◽  
Author(s):  
Adusumilli Srikrishna ◽  
Channabasaveshwar V. Yelamaggad ◽  
Kathiresan Krishnan ◽  
Munirathinam Nethaji
Keyword(s):  
Total Synthesis ◽  
Single Crystal ◽  
X Ray

scholarly journals Bridgehead vicinal diallylation of norbornene derivatives and extension to propellane derivatives via ring-closing metathesis

2016 ◽  
Vol 12 ◽  
pp. 1877-1883 ◽  
Author(s):  
Sambasivarao Kotha ◽  
Rama Gunta
Keyword(s):  
Single Crystal ◽  
Diffraction Analysis ◽  
X Ray Diffraction ◽  
Ring Closing Metathesis ◽  
X Ray ◽  
Synthetic Strategy ◽  
Norbornene Derivatives

Here, we report a simple synthetic strategy to the bridgehead vicinal diallylation of norbornene derivatives. These substrates are useful to generate propellanes via ring-closing metathesis. Single-crystal X-ray diffraction analysis of four compounds led to the realization of configurational correction of earlier reported molecules.

scholarly journals First Total Synthesis and Investigation of the X-ray Crystal Structure of the Pyrano[3,2-a]carbazole Alkaloid Clausenalansine A

Synthesis ◽  
2020 ◽  
Vol 53 (02) ◽  
pp. 359-364
Author(s):  
Hans-Joachim Knölker ◽  
Valerie Lösle ◽  
Olga Kataeva
Keyword(s):  
Crystal Structure ◽  
Total Synthesis ◽  
Lewis Acid ◽  
Oxidative Cyclization ◽  
Formyl Group ◽  
Pyran Ring ◽  
X Ray ◽  
Synthetic Strategy

AbstractWe describe the first total synthesis of the recently discovered pyrano[3,2-a]carbazole alkaloid clausenalansine A. The synthetic strategy for the construction of this formylpyrano[3,2-a]carbazole is based on a sequence of Buchwald–Hartwig coupling, palladium(II)-catalyzed oxidative cyclization, Lewis acid promoted annulation of the pyran ring, and chemoselective oxidation of a methyl to a formyl group.

Die absolute Konfiguration der Juglomycine/The Absolute Configuration of the Juglomycins

1989 ◽  
Vol 44 (3) ◽  
pp. 345-352 ◽  
Author(s):  
Johann Krupa ◽  
Helmut Lackner ◽  
Peter G. Jones ◽  
Karen Schmidt-Bäse ◽  
George M. Sheldrick
Keyword(s):  
Single Crystal ◽  
Structure Analysis ◽  
Absolute Configuration ◽  
X Ray ◽  
The Absolute ◽  
Dibromo Derivative

The absolute configurations of the known juglomycins A (1) and B (2) have been elucidated by single crystal X-ray structure analysis of 1 and its 6,8-dibromo derivative (1b). The structure of 2 has been corrected; it differs from 1 in its configuration at C-4', and not at C-3' as previously assumed. Relationships with the closely related isochromanquinone antibiotics are discussed.

A novel lipid from the brown alga Notheia anomala

1980 ◽  
Vol 33 (4) ◽  
pp. 891 ◽  
Author(s):  
RG Warren ◽  
RJ Wells ◽  
JF Blount
Keyword(s):  
Single Crystal ◽  
Spectral Data ◽  
Absolute Configuration ◽  
Brown Alga ◽  
X Ray ◽  
Relative Stereochemistry ◽  
The Absolute

The brown alga Notheia anomala has yielded a C19 lipid diol, (6S,7S,9R,10R)-6,9-epoxynonadec-18-ene-7,10-diol, as the major component. The structure, assigned on the basis of spectral data, was confirmed by single-crystal X-ray analysis, which also established the relative stereochemistry. The absolute configuration was determined on the monoacetate by the Horeau method.

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