The Hydroxylated, Tetracyclic Bisquinolizidine Alkaloids Baptifoline and Epibaptifoline: Enantioselective Synthesis and Unambiguous Assignment of their Configuration at C-13

2018 ◽  
Vol 2019 (5) ◽  
pp. 895-899
Author(s):  
Jessica Goller ◽  
Christian B. Hübschle ◽  
Matthias Breuning
Keyword(s):  
Enantioselective Synthesis ◽  
Unambiguous Assignment

scholarly journals Enantioselective Synthesis of the Bisabolane Sesquiterpene (+)-1-Hydroxy-1,3,5-Bisabolatrien-10-one and Revision of its Absolute Configuration

2012 ◽  
Vol 7 (4) ◽  
pp. 1934578X1200700 ◽  
Author(s):  
Stefano Serra
Keyword(s):  
Absolute Configuration ◽  
Optical Rotation ◽  
Enantioselective Synthesis ◽  
Positive Sign ◽  
Chiral Building Block ◽  
Chemical Purity ◽  
Unambiguous Assignment ◽  
Biocatalytic Process ◽  
Good Agreement ◽  
Methyl Phenyl

The enantioselective synthesis of ( S)-1-hydroxy-1,3,5-bisabolatrien-10-one 1 is here described. This sesquiterpene was prepared using ( S)-3-(2-methoxy-4-methyl-phenyl)butan-1-ol as a chiral building block. Two different pathways were employed and both turned out to be high yielding, affording 1 in good chemical purity and without any racemization of the existing stereocenter. The spectroscopic data of the synthetic ( S)-1 were in very good agreement with those reported for the natural compound, which was extracted from Juniperus formosana heartwood and from the leaves of J. chinensis. The positive sign of the measured optical rotation value of synthetic ( S)-1 allows the unambiguous assignment of the absolute configuration of (+)-1 as the ( S)-enantiomer. This finding corrects the previous configuration determination which indicated the opposite result. At last, since even ( R)-3-(2-methoxy-4-methyl-phenyl)butan-1-ol is preparable in high enantiomer purity by mean of a different biocatalytic process, the formal synthesis of natural ( R)-1 was also accomplished.

Catalytic enantioselective synthesis of indolizino[8,7-b]indole alkaloid derivatives based on the tandem reaction of tertiary enamides

2021 ◽  
Author(s):  
Xin-Ming Xu ◽  
Ming Xie ◽  
Jiazhu Li ◽  
Mei-Xiang Wang
Keyword(s):  
Indole Alkaloid ◽  
Enantioselective Synthesis ◽  
High Yield ◽  
Tandem Reaction ◽  
Indole Derivatives

An exquisite Pybox/Cu(OTf)2-catalyzed asymmetric tandem reaction of tertiary enamides was developed, which enabled the expeditious synthesis of indolizino[8,7-b]indole derivatives in high yield, excellent enantioselectivity and diastereoselectivity.

Enantioselective Synthesis of Azamerone

2018 ◽  
Author(s):  
Matthew L. Landry ◽  
Grace McKenna ◽  
Noah Burns
Keyword(s):  
Late Stage ◽  
Cross Coupling ◽  
Enantioselective Synthesis ◽  
Selective Synthesis

A concise and selective synthesis of the dichlorinated meroterpenoid azamerone is described. The paucity of tactics for the synthesis of chiral organochlorides motivated the development of unique strategies for accessing these motifs in enantioenriched forms. The route features a novel enantioselective chloroetherification reaction, a Pd-catalyzed cross-coupling between a quinone diazide and a boronic hemiester, and a late-stage tetrazine [4+2]-cycloaddition/oxidation cascade.

Modular, Stereocontrolled Cβ–H/Cα–C Activation of Alkyl Carboxylic Acids

2019 ◽  
Author(s):  
Ming Shang ◽  
Karla S. Feu ◽  
Julien C. Vantourout ◽  
Lisa M. Barton ◽  
Heather L. Osswald ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Heterocyclic Compounds ◽  
Cross Coupling ◽  
Building Blocks ◽  
Enantioselective Synthesis ◽  
Carbon Centers ◽  
Drug Candidates ◽  
Rapid Diversification ◽  
Directing Group ◽  
Compound Series

<div> <div> <div> <p>The union of two powerful transformations, directed C–H activation and decarboxylative cross-coupling, for the enantioselective synthesis of vicinally functionalized alkyl, carbocyclic, and heterocyclic compounds is described. Starting from simple carboxylic acid building blocks, this modular sequence exploits the residual directing group to access more than 50 scaffolds that would be otherwise extremely difficult to prepare. The tactical use of these two transformations accomplishes a formal vicinal difunctionalization of carbon centers in a way that is modular and thus amenable to rapid diversity incorporation. A simplification of routes to known preclinical drug candidates is presented along with the rapid diversification of an antimalarial compound series. </p> </div> </div> </div>

Enantioselective Synthesis of Azamerone

2018 ◽  
Author(s):  
Matthew L. Landry ◽  
Grace McKenna ◽  
Noah Burns
Keyword(s):  
Late Stage ◽  
Cross Coupling ◽  
Enantioselective Synthesis ◽  
Selective Synthesis

A concise and selective synthesis of the dichlorinated meroterpenoid azamerone is described. The paucity of tactics for the synthesis of chiral organochlorides motivated the development of unique strategies for accessing these motifs in enantioenriched forms. The route features a novel enantioselective chloroetherification reaction, a Pd-catalyzed cross-coupling between a quinone diazide and a boronic hemiester, and a late-stage tetrazine [4+2]-cycloaddition/oxidation cascade.

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