scholarly journals Direct Photoexcitation of Benzothiazolines: Acyl Radical Generation and Application to Access Heterocycles

Molecules ◽  
2021 ◽  
Vol 26 (22) ◽  
pp. 6843
Author(s):  
Xiang-Kui He ◽  
Juan Lu ◽  
Hai-Bing Ye ◽  
Lei Li ◽  
Jun Xuan
Keyword(s):  
Natural Products ◽  
Radical Cyclization ◽  
Acyl Radical ◽  
Radical Species ◽  
Complex Molecules ◽  
Radical Generation

An acyl radical generation and functionalization strategy through direct photoexcitation of benzothiazolines has been developed. The formed acyl radical species can either be trapped by quinoxalin-2-ones to realize their C(3)-H functionalization or trigger a cascade radical cyclization with isonitriles to synthesise biologically important phenanthridines. The synthetic value of this protocol can be further illustrated by the modification of quinoxalin-2-ones, containing important natural products and drug-based complex molecules.

scholarly journals Activation modes in biocatalytic radical cyclization reactions

2021 ◽  
Author(s):  
Yuxuan Ye ◽  
Haigen Fu ◽  
Todd K Hyster
Keyword(s):  
Heme Iron ◽  
Radical Cyclization ◽  
Cytochrome P450 Monooxygenases ◽  
Radical Cyclizations ◽  
Cyclization Reactions ◽  
Complex Molecules ◽  
P450 Monooxygenases ◽  
Non Heme Iron ◽  
Essential Reactions ◽  
Isopenicillin N

Abstract Radical cyclizations are essential reactions in the biosynthesis of secondary metabolites and the chemical synthesis of societally valuable molecules. In this review, we highlight the general mechanisms utilized in biocatalytic radical cyclizations. We specifically highlight cytochrome P450 monooxygenases (P450s) involved in the biosynthesis of mycocyclosin and vancomycin, non-heme iron- and α-ketoglutarate-dependent dioxygenases (Fe/αKGDs) used in the biosynthesis of kainic acid, scopolamine, and isopenicillin N, and radical S-adenosylmethionine (SAM) enzymes that facilitate the biosynthesis of oxetanocin A, menaquinone, and F420. Beyond natural mechanisms, we also examine repurposed flavin-dependent ‘ene’-reductases (ERED) for non-natural radical cyclization. Overall, these general mechanisms underscore the opportunity for enzymes to augment and enhance the synthesis of complex molecules using radical mechanisms.

scholarly journals Foods, the Best Way to Take Antioxidant Natural Products

Foods ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 19
Author(s):  
Maria Eduarda Machado Araújo ◽  
Alice Martins
Keyword(s):  
Natural Products ◽  
The Body ◽  
Radical Species

Antioxidants are powerful compounds that help the body to destroy the excess of endogenous radical species responsible for many severe conditions like neurodegenerative, inflammatory, and cardiovascular impairments, and even some forms of cancer [...]

Rapid construction of the 6/6/5 tricyclic framework via a tandem radical cyclization reaction and its application to the synthesis of 5-epi-7-deoxy-isoabietenin A

2017 ◽  
Vol 4 (11) ◽  
pp. 2211-2215 ◽  
Author(s):  
Hao Zhang ◽  
Shiqiang Ma ◽  
Zhimin Xing ◽  
Lin Liu ◽  
Bowen Fang ◽  
...  
Keyword(s):  
Natural Products ◽  
Radical Cyclization ◽  
Cyclization Reaction ◽  
Rapid Construction

A tandem radical cyclization towards the 6/6/5 tricyclic skeleton, which exists in numerous natural products, was developed in modest to good yields.

Tin-Mediated Radical Cyclization Reactions

2021 ◽  
Vol 25 ◽  
Author(s):  
Saima malik ◽  
Aditya G. Lavekar ◽  
Bimal Krishna Banik
Keyword(s):  
Organic Compounds ◽  
Organic Synthesis ◽  
Biological Significance ◽  
Radical Cyclization ◽  
Organic Reactions ◽  
Cyclization Reactions ◽  
Complex Molecules ◽  
Radical Chemistry ◽  
Wide Range

: The radical was first come into existence in 1900 by Gomberg, where the triphenylmethane radical was explored. Thus, even to date, two centuries have seen radical chemistry as the methodology of preference in organic synthesis. Due to the fascinating nature of the radical-mediated cyclization reactions, it always caught the eye of organic chemists for the synthesis of novel organic compounds with diverse stereochemistry. Moreover, the development of radical methods further proves beneficial for the synthesis by providing atom- and step-economical methods to complex molecules. Among these, where radical chemistry has been employed, the use of tin-based radical annulation is the most common and widely used field for the synthesis of a wide range of organic reactions with medicinal importance. In this review, we compiled recent tin-mediated radical cyclization reactions toward the synthesis of molecules of biological significance.

scholarly journals Pd(II)-Catalyzed C-H Acylation of (Hetero)arenes—Recent Advances

Molecules ◽  
2020 ◽  
Vol 25 (14) ◽  
pp. 3247 ◽  
Author(s):  
Carlos Santiago ◽  
Nuria Sotomayor ◽  
Esther Lete
Keyword(s):  
Natural Products ◽  
Toxic Metal ◽  
Complex Molecules ◽  
Metal Waste ◽  
Recent Advances ◽  
Aryl Ketones ◽  
Recent Developments ◽  
Further Development

Di(hetero)aryl ketones are important motifs present in natural products, pharmaceuticals or agrochemicals. In recent years, Pd(II)-catalyzed acylation of (hetero)arenes in the presence of an oxidant has emerged as a catalytic alternative to classical acylation methods, reducing the production of toxic metal waste. Different directing groups and acyl sources are being studied for this purpose, although further development is required to face mainly selectivity problems in order to be applied in the synthesis of more complex molecules. Selected recent developments and applications are covered in this review.

scholarly journals Expedient Access to Enantiopure Cyclopentanic Natural Products: Total Synthesis of (-)-Cyclonerodiol

2015 ◽  
Vol 10 (1) ◽  
pp. 1934578X1501000
Author(s):  
Carmen Pérez Morales ◽  
M. Mar Herrador ◽  
José F. Quílez del Moral ◽  
Alejandro F. Barrero
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Radical Cyclization ◽  
Formal Synthesis ◽  
Common Precursor ◽  
Enantiospecific Synthesis ◽  
Optically Pure

Following the principles of collective total synthesis, a number of natural products sharing an optically pure, multifunctional, cyclopentanic core were synthesized from a common precursor: plinol A (1). This intermediate was efficiently obtained in only four steps from (-)-linalool (2) using as the key step a Ti(III)-mediated diastereoselective radical cyclization. The feasibility of this approach was confirmed with the expedient enantiospecific synthesis of cyclonerodiol (3), and the formal synthesis of chocol G (4) and piperitone (5).

Exploration and engineering of biosynthetic pathways in the marine actinomycete Salinispora tropica

2009 ◽  
Vol 81 (6) ◽  
pp. 1075-1084 ◽  
Author(s):  
Markus Nett ◽  
Bradley S. Moore
Keyword(s):  
Natural Products ◽  
Metabolic Pathways ◽  
Anticancer Agent ◽  
Complex Molecules ◽  
Dna Cleaving ◽  
Metabolic Plasticity ◽  
Salinosporamide A ◽  
Salinispora Tropica ◽  
Marine Actinomycete ◽  
Key Genes

In recent years, members of the marine actinomycete genus Salinispora have proven to be a precious source of structurally diverse secondary metabolites, including the potent anticancer agent salinosporamide A and the enediyne-derived sporolides. The tremendous potential of these marine-dwelling microbes for natural products biosynthesis, however, was not fully realized until sequencing of the Salinispora tropica genome revealed the presence of numerous orphan biosynthetic loci besides a plethora of rare metabolic pathways. This contribution summarizes the biochemical exploration of this prolific organism, highlighting studies in which genome-based information was exploited for the discovery of new enzymatic processes and the engineering of unnatural natural products. Inactivation of key genes within the salinosporamide pathway has expanded its inherent metabolic plasticity and enabled access to various salinosporamide derivatives by mutasynthesis. New insights into the biosynthesis of the sporolides allowed us to increase production titers of these structurally complex molecules, thereby providing the means to search for the DNA cleaving presporolide enediyne.

ChemInform Abstract: Radical Cyclization Using a Thioacetal Group for Radical Generation.

ChemInform ◽  
2010 ◽  
Vol 27 (44) ◽  
pp. no-no
Author(s):  
A. NISHIDA ◽  
N. KAWAHARA ◽  
M. NISHIDA ◽  
O. YONEMITSU
Keyword(s):  
Radical Cyclization ◽  
Radical Generation
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