Total Synthesis of the Pseudoindoxyl Class of Natural Products

Author(s):  
Pawan Surendra Dhote ◽  
Pitambar Patel ◽  
Kumar Vanka ◽  
Chepuri Ramana

The pseudoindoxyl sub-structural motif, amongst the large set of the indole class of alkaloids, represents a unique subset of the oxygenated indole class of the alkaloids family. A majority of...

2021 ◽  
Author(s):  
Fan Xu ◽  
Myles Smith

The indoxyl unit is a common structural motif in alkaloid natural products and bioactive compounds. Here, we report a general method that transforms readily available 2-substituted indoles into 2,2-disubstituted indoxyls via nucleophile coupling with a 2-alkoxyindoxyl intermediate and showcase its utility in short total syntheses of the alkaloids brevianamide A (7 steps) and trigonoliimine C (6 steps). The developed method is operationally simple and demonstrates broad scope in terms of nucleophile identity and indole substitution, tolerating 2-alkyl substituents and free indole N–H groups, elements beyond the scope of most prior approaches. Spirocyclic indoxyl products are also accessible via intramolecular nucleophilic trapping.


Synthesis ◽  
2017 ◽  
Vol 49 (22) ◽  
pp. 4899-4916 ◽  
Author(s):  
Rongbiao Tong ◽  
Zhihong Zhang

Being different from 2,6-cis-tetrahydropyrans (2,6-cis-THPs), the corresponding 2,6-trans-THPs are thermodynamically less stable and more challenging to construct. The fact that there are many natural products and/or bioactive molecules containing this 2,6-trans-THP subunit has led to the development of many efficient synthetic approaches to access 2,6-trans-THPs. This review summarizes various synthetic methods reported for this structural motif and/or related applications in the total synthesis of natural products.1 Introduction2 Nucleophilic Addition to an Oxocarbenium Ion (Strategy A)3 Intramolecular Oxa-Michael Addition (Strategy B)4 Intermolecular Michael Addition to Dihydropyranones (Strategy A)5 The Heck–Matsuda (Strategy A) Reaction and Oxa-Heck Cyclization (Strategy B)6 Intramolecular SN2 Substitution and Epoxide Opening (Strategy B)7 Miscellaneous Methods8 Conclusion and Outlook


2021 ◽  
Author(s):  
Fan Xu ◽  
Myles Smith

The indoxyl unit is a common structural motif in alkaloid natural products and bioactive compounds. Here, we report a general method that transforms readily available 2-substituted indoles into 2,2-disubstituted indoxyls via nucleophile coupling with a 2-alkoxyindoxyl intermediate and showcase its utility in short total syntheses of the alkaloids brevianamide A (7 steps) and trigonoliimine C (6 steps). The developed method is operationally simple and demonstrates broad scope in terms of nucleophile identity and indole substitution, tolerating 2-alkyl substituents and free indole N–H groups, elements beyond the scope of most prior approaches. Spirocyclic indoxyl products are also accessible via intramolecular nucleophilic trapping.


2021 ◽  
Vol 17 ◽  
pp. 58-82
Author(s):  
Bidyut Kumar Senapati

The inthomycin family of antibiotics, isolated from Streptomyces strains, are interesting molecules for synthesis due to their characteristic common oxazole polyene chiral allylic β-hydroxycarbonyl fragments and significant biological activities. The full structural motif of the inthomycins is found in several more complex natural products including the oxazolomycins, 16-methyloxazolomycin, curromycins A and B, and KSM-2690. This review summarises the application of various efforts towards the synthesis of inthomycins and their analogues systematically.


2020 ◽  
Vol 17 ◽  
Author(s):  
Majid M. Heravi ◽  
Tayebe Momeni ◽  
Vahideh Zadsirjan ◽  
Leila Mohammadi

: Dess–Martin periodinane (DMP), is a commercially available chemical, frequently being utilized as a mild oxidative agent for the selective oxidation of primary and secondary alcohols to their corresponding aldehydes and ketones, respectively. DMP shows several merits over other common oxidative agent such as chromium- and DMSO-based oxidants, thus it is habitually employed in the total synthesis of natural products. In this review, we try to underscore the applications of DMP as an effective oxidant in an appropriate step (steps) in the multistep total synthesis of natural products.


Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 720
Author(s):  
Satomi Niwayama

Symmetric organic compounds are generally obtained inexpensively, and therefore they can be attractive building blocks for the total synthesis of various pharmaceuticals and natural products. The drawback is that discriminating the identical functional groups in the symmetric compounds is difficult. Water is the most environmentally benign and inexpensive solvent. However, successful organic reactions in water are rather limited due to the hydrophobicity of organic compounds in general. Therefore, desymmetrization reactions in aqueous media are expected to offer versatile strategies for the synthesis of a variety of significant organic compounds. This review focuses on the recent progress of desymmetrization reactions of symmetric organic compounds in aqueous media without utilizing enzymes.


2021 ◽  
Vol 57 (27) ◽  
pp. 3307-3322
Author(s):  
Debobrata Paul ◽  
Ashis Kundu ◽  
Sanu Saha ◽  
Rajib Kumar Goswami

This feature article highlights total synthesis as one of the reliable tools for the structural confirmation of natural products.


2021 ◽  
Vol 67 ◽  
pp. 152895
Author(s):  
Shu Takahashi ◽  
Aoi Kimishima ◽  
Tomoyasu Hirose ◽  
Takeshi Yamada ◽  
Akihiro Sugawara ◽  
...  

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