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Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions
Published on: July 17, 2020
Cryptic halogenation reactions in natural product biosynthesis.
Sanjoy Adak1, Bradley S Moore1,2
1Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, 92093, USA. bsmoore@ucsd.edu.
Enzymatic halogenation reactions are vital for natural product synthesis. This review covers "cryptic" halogenation, where halogens are transiently incorporated and lost during biosynthesis, activating molecules for diverse chemical transformations.
Area of Science:
- Biochemistry
- Natural Product Biosynthesis
- Enzymology
Background:
- Enzymatic halogenation is crucial for synthesizing numerous halogenated natural products.
- Halogenases can transiently incorporate halogens into biosynthetic intermediates.
- These incorporated halogens are lost in later steps, hence termed 'cryptic'.
Purpose of the Study:
- To review the current understanding of cryptic halogenation reactions in natural product biosynthesis.
- To highlight the role of these transient halogens in activating molecules for further biosynthetic transformations.
Main Methods:
- Literature review of studies on halogenases and natural product biosynthesis up to December 2020.
- Analysis of reported mechanisms involving cryptic halogenation.
- Compilation of examples of cryptic halogenation in various biosynthetic pathways.
Main Results:
- Identified several halogenases that utilize cryptic halogenation.
- Documented diverse chemical reactions activated by cryptic halogens, including cyclopropanation, alkyne formation, alkylation, and C-C bond formations.
- Established that the halogen atom is not present in the final natural product.
Conclusions:
- Cryptic halogenation represents a significant, yet often overlooked, strategy in natural product biosynthesis.
- Understanding these reactions provides insights into novel enzymatic mechanisms and potential applications in synthetic biology.
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