scholarly journals Stereoselective synthesis of four possible isomers of streptopyrrolidine

2011 ◽  
Vol 7 ◽  
pp. 34-39 ◽  
Author(s):  
Debendra K Mohapatra ◽  
Barla Thirupathi ◽  
Pragna P Das ◽  
Jhillu S Yadav
Keyword(s):  
Ethyl Acetate ◽  
Natural Product ◽  
Lewis Acid ◽  
Absolute Configuration ◽  
Stereoselective Synthesis ◽  
Analytical Data ◽  
Efficient Manner ◽  
Type Reaction ◽  
Highly Efficient ◽  
The Absolute

The synthesis of (4R,5R)-streptopyrrolidine (1), (4S,5R)-streptopyrrolidine (2) (4R,5S)-streptopyrrolidine (3) and (4S,5S)-streptopyrrolidine (4) have been achieved in a concise and highly efficient manner via a highly stereoselective aldol type reaction with the trimethylsilyl enolate of ethyl acetate and Lewis acid mediated lactamization as the key reactions in ≈42% yield over six steps starting from D-phenylalanine and L-phenylalanine, respectively. The absolute configuration of the natural product was shown to be (4S,5S) by comparing its spectral and analytical data with the reported values.

Evaluation of Different Synthetic Routes to (2R,3R)-3-Hydroxymethyl-2-(4-hydroxy- 3-methoxyphenyl)-1,4-Benzodioxane-6-Carbaldehyde

2020 ◽  
Vol 23 (26) ◽  
pp. 2960-2968
Author(s):  
Renáta Kertiné Ferenczi ◽  
Tünde-Zita Illyés ◽  
Sándor Balázs Király ◽  
Gyula Hoffka ◽  
László Szilágyi ◽  
...  
Keyword(s):  
Absolute Configuration ◽  
Stereoselective Synthesis ◽  
Cotton Effect ◽  
Enantioselective Synthesis ◽  
Aryl Group ◽  
Target Molecule ◽  
Synthetic Routes ◽  
The Absolute

The reported enantioselective synthesis for the preparation of (+)-(2R,3R)-2-(4- hydroxy-3-methoxyphenyl)-3-hydroxymethyl-1,4-benzodioxane-6-carbaldehyde, precursor for the stereoselective synthesis of bioactive flavanolignans, could not be reproduced. Thus, the target molecule was prepared via the synthesis and separation of diastereomeric O-glucosides. TDDFT-ECD calculations and the 1,4-benzodioxane helicity rule were utilized to determine the absolute configuration. ECD calculations also confirmed that the 1Lb Cotton effect is governed by the helicity of the heteroring, while the higher-energy ECD transitions reflect mainly the orientation of the equatorial C-2 aryl group.

scholarly journals Recent Developments in Polyene Cyclizations and Their Applications in Natural Product Synthesis

Synthesis ◽  
2018 ◽  
Vol 51 (01) ◽  
pp. 67-82 ◽  
Author(s):  
Anthony Barrett ◽  
Tsz-Kan Ma ◽  
Thomas Mies
Keyword(s):  
Transition Metal ◽  
Natural Product ◽  
Lewis Acid ◽  
Multiple Bond ◽  
Natural Product Synthesis ◽  
Cyclization Reactions ◽  
Cascade Cyclizations ◽  
Highly Efficient ◽  
Recent Developments ◽  
Radical Cascade

Cascade polyene cyclization reactions are highly efficient and elegant bioinspired transformations that involve simultaneous multiple bond constructions to rapidly generate complex polycyclic molecules. This review summarizes the most prominent work on a variety of cationic and radical cascade cyclizations and their applications in natural product synthesis published between 2014 and 2018.1 Introduction2 Cationic Polyene Cyclizations2.1 Lewis Acid Mediated Polyene Cyclizations2.2 Brønsted Acid Mediated Polyene Cyclizations2.3 Halogen Electrophile Initiated Polyene Cyclizations2.4 Sulfur Electrophile Initiated Polyene Cyclizations2.5 Transition-Metal-Mediated Cationic Polyene Cyclizations3 Radical Polyene Cyclizations3.1 Transition-Metal-Mediated Radical Polyene Cyclizations3.2 Photocatalyst-Mediated Polyene Cyclizations4 Origin of Stereocontrol in Polyene Cyclizations5 Conclusion

scholarly journals Determination of the Absolute Configuration of the Pseudo‐Symmetric Natural Product Elatenyne by the Crystalline Sponge Method

2016 ◽  
Vol 55 (8) ◽  
pp. 2678-2682 ◽  
Author(s):  
Sylvia Urban ◽  
Robert Brkljača ◽  
Manabu Hoshino ◽  
Shoukou Lee ◽  
Makoto Fujita
Keyword(s):  
Natural Product ◽  
Absolute Configuration ◽  
The Absolute

scholarly journals De novo synthesis, structural assignment and biological evaluation of pseudopaline, a metallophore produced by Pseudomonas aeruginosa

2019 ◽  
Vol 10 (27) ◽  
pp. 6635-6641 ◽  
Author(s):  
Jian Zhang ◽  
Tianhu Zhao ◽  
Rongwen Yang ◽  
Ittipon Siridechakorn ◽  
Sanshan Wang ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Total Synthesis ◽  
Natural Product ◽  
Absolute Configuration ◽  
De Novo ◽  
Biological Evaluation ◽  
De Novo Synthesis ◽  
Structural Assignment ◽  
The Absolute

The first total synthesis and isolation of pseudopaline was reported, which allows determination and confirmation of the absolute configuration of the natural product.

scholarly journals Chiral Resolution and Absolute Configuration of 3α,6β-Dicinnamoyloxytropane and 3α,6β-Di(1-ethyl-1H-pyrrol-2-ylcarbonyloxy)tropane, Constituents of Erythroxylum Species

2014 ◽  
Vol 9 (1) ◽  
pp. 1934578X1400900 ◽  
Author(s):  
Marcelo A. Muñoz ◽  
Solange Arriagada ◽  
Pedro Joseph-Nathan
Keyword(s):  
Stationary Phase ◽  
Natural Product ◽  
Absolute Configuration ◽  
Optical Rotation ◽  
Normal Phase ◽  
Vibrational Circular Dichroism ◽  
Chiral Resolution ◽  
Case Characteristic ◽  
The Absolute

Chiral resolution of (±)-3α,6β-dicinnamoyloxytropane (1) and (±)-3α,6β-di(1-methyl-1 H-pyrrol-2-ylcarbonyloxy)tropane (2), prepared by esterification of (±)-3α,6β-tropanediol (3), was achieved using an amylose-derived HPLC stationary phase and normal phase conditions. The corresponding vibrational circular dichroism (VCD) spectra provided the absolute configuration of the enantiomers as (-)-(3 R,6 R)-1, (+)-(3S,6S)- 1, (-)-(3 R,6 R)-2 and (+)-(3S,6S)- 2. In each case, characteristic VCD bands for the absolute configuration determination of the 3α,6β-tropandiol esters were observed. While the absolute configuration of natural 1, previously isolated from Erythroxylum hypericifolium, could not be established due to the lack of literature optical rotation values, that of catuabine E, previously isolated from E. vacciniifolium, is now assigned as (-)-(3 R,6 R)-2 by comparison with the optical rotation values of the prepared samples and the reported rotation of the natural product.

Total synthesis of (+)-(S)-angustureine and the determination of the absolute configuration of the natural product angustureine

2005 ◽  
Vol 16 (4) ◽  
pp. 827-831 ◽  
Author(s):  
Chumpol Theeraladanon ◽  
Mitsuhiro Arisawa ◽  
Masako Nakagawa ◽  
Atsushi Nishida
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Absolute Configuration ◽  
The Absolute
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