Lipase-Catalyzed Site-Selective Deacetylation of Sterically Hindered Naphthohydroquinone Diacetate and Its Application to the Synthesis of a Heterocyclic Natural Product

Heterocycles ◽  
2019 ◽  
Vol 99 (1) ◽  
pp. 625 ◽  
Author(s):  
Takeshi Sugai ◽  
Riichi Hashimoto ◽  
Ayaka Sakakura ◽  
Kengo Hanaya ◽  
Shuhei Higashibayashi
Keyword(s):  
Natural Product ◽  
Sterically Hindered ◽  
Site Selective ◽  
Selective Deacetylation

Synthesis of Conjugated Triynes via Alkyne Metathesis

2019 ◽  
Author(s):  
Idriss Curbet ◽  
Sophie Colombel-Rouen ◽  
Romane Manguin ◽  
Anthony Clermont ◽  
Alexandre Quelhas ◽  
...  
Keyword(s):  
Steric Hindrance ◽  
High Selectivity ◽  
Alkyne Metathesis ◽  
Cross Metathesis ◽  
Synthetic Strategy ◽  
Sterically Hindered ◽  
Site Selective

<div> <div> <div> <div> <p>The synthesis of conjugated triynes by molybdenum-catalyzed alkyne metathesis is reported. Strategic to the success of this approach is the utilization of sterically-hindered diynes that allowed for the site- selective alkyne metathesis to produce the desired con- jugated triyne products. The steric hindrance of alkyne moiety was found to be crucial in preventing the for- mation of diyne byproducts. This novel synthetic strategy was amenable to self- and cross-metathesis providing straightforward access to the corresponding symmetrical and dissymmetrical triynes with high selectivity. </p> </div> </div> </div> </div>

Site-selective phenol acylation mediated by thioacids via visible light photoredox catalysis

2018 ◽  
Vol 5 (8) ◽  
pp. 1312-1319 ◽  
Author(s):  
Lili Shi ◽  
Hongxin Liu ◽  
Luqiong Huo ◽  
Yaqian Dang ◽  
Yu Wang ◽  
...  
Keyword(s):  
Visible Light ◽  
Natural Product ◽  
Hydroxyl Group ◽  
Photoredox Catalysis ◽  
Phenolic Esters ◽  
Site Selective

Site-selective phenol acylation mediated by thioacids via photoredox catalysis is described. This protocol provided facile access to an array of phenolic esters with exclusive acylation priority of phenol hydroxyl group to alcoholic one. Its utility was also demonstrated by the modification of biologically meaningful natural product.

scholarly journals Catalysis-Enabled Access to Cryptic Geldanamycin Oxides

2020 ◽  
Author(s):  
Margaret J. Hilton ◽  
Christopher Brackett ◽  
Brandon Q. Mercado ◽  
Brian S. J. Blagg ◽  
Scott Miller
Keyword(s):  
Natural Product ◽  
Reaction Pathway ◽  
Outer Sphere ◽  
Oxidation Reactions ◽  
Biological Assays ◽  
Peptide Catalysts ◽  
Isolation And Characterization ◽  
Site Selective ◽  
New Compounds ◽  
Stereoselective Oxidation

Catalytic, selective modifications of natural products can be a fertile platform for unveiling not only new natural product analogs with altered biological activity, but also for revealing new reactivity and selectivity hierarchies for embedded functional groups in complex environments. Motivated by these intersecting aims, we report site and stereoselective oxidation reactions of geldanamycin facilitated by aspartyl-peptide catalysts. Through the isolation and characterization of four new geldanamycin oxides, we discovered a synergistic effect between lead peptide-based catalysts and geldanamycin, resulting in an unexpected reaction pathway. Curiously, it seems unlikely that our discoveries would not have been possible absent the outer sphere interactions intrinsic to both the catalyst and the natural product. The result is a set of new “meta” catalytic reactions that deliver both unknown and previously incompletely characterized geldanamycin analogs. Enabled by the catalytic, site-selective epoxidation of geldanamycin, biological assays were carried out to document the bioactivities of the new compounds.<div><br></div>

scholarly journals Flavin-dependent halogenases catalyze enantioselective olefin halocyclization

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Dibyendu Mondal ◽  
Brian F. Fisher ◽  
Yuhua Jiang ◽  
Jared C. Lewis
Keyword(s):  
Organic Chemistry ◽  
Catalytic Activity ◽  
Protein Engineering ◽  
Natural Product ◽  
Active Site ◽  
Natural Product Biosynthesis ◽  
Bond Forming ◽  
Reaction Optimization ◽  
Wide Range ◽  
Site Selective

AbstractHalocyclization of alkenes is a powerful bond-forming tool in synthetic organic chemistry and a key step in natural product biosynthesis, but catalyzing halocyclization with high enantioselectivity remains a challenging task. Identifying suitable enzymes that catalyze enantioselective halocyclization of simple olefins would therefore have significant synthetic value. Flavin-dependent halogenases (FDHs) catalyze halogenation of arene and enol(ate) substrates. Herein, we reveal that FDHs engineered to catalyze site-selective aromatic halogenation also catalyze non-native bromolactonization of olefins with high enantioselectivity and near-native catalytic proficiency. Highly selective halocyclization is achieved by characterizing and mitigating the release of HOBr from the FDH active site using a combination of reaction optimization and protein engineering. The structural origins of improvements imparted by mutations responsible for the emergence of halocyclase activity are discussed. This expansion of FDH catalytic activity presages the development of a wide range of biocatalytic halogenation reactions.

Total synthesis of conosilane A via a site-selective C–H functionalization strategy

2018 ◽  
Vol 54 (8) ◽  
pp. 912-915 ◽  
Author(s):  
Ziyun Yuan ◽  
Xiaojun Hu ◽  
Hao Zhang ◽  
Lin Liu ◽  
Peng Chen ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Organic Syntheses ◽  
A Site ◽  
Site Selective

The strategy developed for the first total synthesis of highly oxygenated natural product conosilane A involving double manipulation of allylic C(sp3)–H functionalization renders the power of C–H functionalization in organic syntheses.

Site-selective Csp 3 -H aryloxylation of natural product Tanshinone IIA and its analogues

2017 ◽  
Vol 58 (19) ◽  
pp. 1822-1825 ◽  
Author(s):  
Bing Liang ◽  
Shujuan Yu ◽  
Jie Li ◽  
Fan Wang ◽  
Gaolin Liang ◽  
...  
Keyword(s):  
Natural Product ◽  
Tanshinone Iia ◽  
Site Selective

Palladium catalysed meta-C–H functionalization reactions

2016 ◽  
Vol 14 (24) ◽  
pp. 5440-5453 ◽  
Author(s):  
Aniruddha Dey ◽  
Soumitra Agasti ◽  
Debabrata Maiti
Keyword(s):  
Drug Discovery ◽  
Natural Product ◽  
Natural Product Synthesis ◽  
Material Sciences ◽  
Directing Group ◽  
Site Selective

The directing group assisted site selective C–H functionalization approach is having a continuous impact in the field of natural product synthesis, drug discovery and material sciences.

Synthesis of Conjugated Triynes via Alkyne Metathesis

2019 ◽  
Author(s):  
Idriss Curbet ◽  
Sophie Colombel-Rouen ◽  
Romane Manguin ◽  
Anthony Clermont ◽  
Alexandre Quelhas ◽  
...  
Keyword(s):  
Steric Hindrance ◽  
High Selectivity ◽  
Alkyne Metathesis ◽  
Cross Metathesis ◽  
Synthetic Strategy ◽  
Sterically Hindered ◽  
Site Selective

<div> <div> <div> <div> <p>The synthesis of conjugated triynes by molybdenum-catalyzed alkyne metathesis is reported. Strategic to the success of this approach is the utilization of sterically-hindered diynes that allowed for the site- selective alkyne metathesis to produce the desired con- jugated triyne products. The steric hindrance of alkyne moiety was found to be crucial in preventing the for- mation of diyne byproducts. This novel synthetic strategy was amenable to self- and cross-metathesis providing straightforward access to the corresponding symmetrical and dissymmetrical triynes with high selectivity. </p> </div> </div> </div> </div>

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