Synthesis of Dichotomin A: Use of a Penicillamine-Derived Pseudoproline to Furnish Native Valine Residues

2015 ◽  
Vol 68 (4) ◽  
pp. 627 ◽  
Author(s):  
Michelle S. Y. Wong ◽  
Deni Taleski ◽  
Katrina A. Jolliffe
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Side Chain ◽  
Linear Peptide ◽  
Cyclic Hexapeptide ◽  
Peptide Precursors ◽  
Head To Tail Cyclization

The total synthesis of cyclic hexapeptide dichotomin A from linear peptide precursors containing penicillamine-derived pseudoproline residues is reported. The incorporation of a pseudoproline residue led to a faster reaction and higher head-to-tail cyclization yields in comparison to linear precursors containing the native valine residue. However, deprotection of the pseudoproline resulted in significant amounts of a by-product in which a threonine side chain had undergone dehydration, resulting in a low overall yield of the natural product.

scholarly journals Regioselective side-chain amination of 2-alkyl azacycles by radical translocation: total synthesis of tetraponerine T8

2021 ◽  
Author(s):  
Samuel D. Griggs ◽  
Alejandro Martin-Roncero ◽  
Adam Nelson ◽  
Stephen P. Marsden
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Side Chain

Radical translocation facilitates the regioselective γ-amination of 2-alkyl-substituted azacycles, leading to 1,3-diamines including the alkaloidal natural product tetraponerine T8.

Studies Toward the Total Synthesis and Stereochemical Assignment of Microspinosamide

2015 ◽  
Vol 68 (12) ◽  
pp. 1885 ◽  
Author(s):  
Gajan Santhakumar ◽  
Richard J. Payne
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Chemical Ligation ◽  
Stereochemical Assignment ◽  
Linear Peptide ◽  
Cyclic Depsipeptide ◽  
Peptide Thioester ◽  
Structural Differences

Efforts toward the total synthesis and stereochemical assignment of the cyclic depsipeptide natural product microspinosamide are described. A single diastereoisomer was targeted corresponding to the predicted structure of the natural product incorporating a (2S, 3R)-β-hydroxy-p-bromophenylalanine residue. Assembly was achieved through the initial synthesis of a cyclic depsipeptide and a linear peptide thioester fragment by solid-phase peptide synthesis, followed by fusion of the two fragments through a native chemical ligation–oxidation protocol. Extensive spectroscopic analysis showed structural differences to the isolated natural product, suggesting that a diastereoisomer of microspinosamide had been synthesised. This work lays the foundation for the future synthesis of the correct diastereoisomer.

Total synthesis of (–)-pateamine A, a novel immunosuppressive agent from Mycale sp

2004 ◽  
Vol 82 (2) ◽  
pp. 353-365 ◽  
Author(s):  
Gerald Pattenden ◽  
Douglas J Critcher ◽  
Modesto Remuiñán
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Marine Sponge ◽  
Coupling Reaction ◽  
Immunosuppressive Agent ◽  
Side Chain ◽  
Amino Ester ◽  
Stille Reaction ◽  
Amino Esters ◽  
Pateamine A

A convergent synthesis of the unique thiazole-containing polyene bis-lactone pateamine A (1) isolated from the marine sponge Mycale sp is described. The synthesis features the ubiquitous Stille sp2–sp2 coupling reaction to elaborate the E,Z-diene macrolide core 23 and the all-E polyenamine side chain in the natural product. It also highlights the scope for enantiopure sulfinimine intermediates in the synthesis of chiral β-amino ester moieties in complex structures.Key words: pateamine A, immunosuppressive agent from marine sponge Mycale sp, total synthesis, novel 19-membered bis-lactone, thiazole metabolite, polyenamine, Stille reaction, sulfinimines, chiral β-amino esters.

A Ruthenium-Catalyzed C–H Activation Strategy as an Efficient Shortcut in the Total Synthesis of 6,8-Dimethoxy-1,3-dimethyl­isoquinoline

Synthesis ◽  
2019 ◽  
Vol 51 (20) ◽  
pp. 3908-3914
Author(s):  
Santiago Fonzo ◽  
Didier F. Vargas ◽  
Teodoro S. Kaufman
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Side Chain ◽  
One Pot ◽  
Microwave Assisted ◽  
Efficient Route ◽  
Carbon Side Chain

A short and convenient total synthesis of 6,8-dimethoxy-1,3-dimethylisoquinoline, employing a C–H activation/alkenylation strategy, is reported. The approach involves the CeCl3·7H2O-promoted methoximation of 2,4-dimethoxyacetophenone and a methoxime-directed ruthenium-catalyzed allylation. This was followed by a one-pot, ruthenium-catalyzed allyl to propenyl isomerization and a microwave-assisted 6π-azaelectrocylization to complete the sequence. This approach, which entails a shortcut in the synthetic management of the three-carbon side chain, is an improved and more efficient route toward the natural product, which facilitated its access in just three steps and 27.3% overall yield.

scholarly journals Recent Advances in the Total Synthesis of Tetramic Acid-Containing Natural Products

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Wen-Ju Bai ◽  
Chen Lu ◽  
Xiqing Wang
Keyword(s):  
Organic Chemistry ◽  
Natural Products ◽  
Total Synthesis ◽  
Natural Product ◽  
Side Chain ◽  
Tetramic Acid ◽  
Unique Type ◽  
Recent Advances ◽  
Chemistry Community

With incredible bioactivities and fascinating structural complexities, tetramic acid- (TA-) containing natural products have attracted favorable attention among the organic chemistry community. Although the construction of the TA core is usually straightforward, the intricate C3-side chain sometimes asks for some deliberative strategy so as to fulfill an elegant total synthesis. This review mainly covers some exceptional synthetic examples for each type of natural product in recent years, showcasing the great achievements as well as unsettled obstacles in this area, in the hope of accelerating the synthetic and biological investigations for this unique type of natural product.

Progress Toward The Total Synthesis Of The Marine Natural Product Karlotoxin 5

Planta Medica ◽  
2013 ◽  
Vol 79 (10) ◽  
Author(s):  
M Albadry ◽  
Y Zou ◽  
Y Takahashi ◽  
A Waters ◽  
M Hossein ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Marine Natural Product

Total Synthesis of the Antitumor Depsipeptide FE399 and its S-Benzyl Derivative: A Macrolactamization Approach

2020 ◽  
Author(s):  
Takayuki Tonoi ◽  
Miyuki Ikeda ◽  
Teruyuki Sato ◽  
Ryo Kawahara ◽  
Takatsugu Murata ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Total Synthesis ◽  
Natural Product ◽  
Condensation Reaction ◽  
Practical Method ◽  
Equilibrium Mixture ◽  
Conformational Isomers ◽  
Single Isomer

<div>An efficient and practical method for the synthesis of (9R,14R,17R)-FE399, a novel antitumor bicyclic depsipeptide, was developed. A 2-methyl-6-nitrobenzoic anhydride (MNBA)-mediated dehydration condensation reaction was effectively employed for the formation of the 16-membered macrocyclic depsipeptide moiety of FE399. FE399 was found to exist as an inseparable equilibrium mixture of conformational isomers; the mixture was quantitatively transformed into the corresponding S-benzyl product and isolated as a single isomer. Thus, we could confirm that the molecular structure of FE399 obtained by this method is identical to that of the natural product.</div>

A One-Pot Chemoenzymatic Synthesis of (2S,4R)-4-Methylproline Enables the First Total Synthesis of Antiviral Lipopeptide Cavinafungin B

2018 ◽  
Author(s):  
Christian R. Zwick ◽  
Hans Renata
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Complex Molecule ◽  
Molecular Target ◽  
Chemoenzymatic Synthesis ◽  
General Strategy ◽  
One Pot

We report an efficient ten-step synthesis of antiviral natural product cavinafungin B in 37% overall yield. By leveraging a one-pot chemoenzymatic synthesis of (2S,4R)-4-methylproline and oxazolidine-tethered (Rink-Boc-ATG-resin) SPPS methodology, the assembly of our molecular target could be conducted in an efficient manner.This general strategy could prove amenable to the construction of other natural and unnatural linear lipopeptides. The value of incorporating biocatalytic steps in complex molecule synthesis is highlighted by this work.

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