Indole synthesis by radical cyclization ofo-alkenylphenyl isocyanides and its application to the total synthesis of natural products

2002 ◽  
Vol 2 (1) ◽  
pp. 37-45 ◽  
Author(s):  
Hidetoshi Tokuyama ◽  
Tohru Fukuyama
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Radical Cyclization ◽  
Indole Synthesis

scholarly journals Stereocontrolled total synthesis of (+)-vinblastine

2003 ◽  
Vol 75 (1) ◽  
pp. 29-38 ◽  
Author(s):  
Satoshi Yokoshima ◽  
T. Ueda ◽  
S. Kobayashi ◽  
A. Sato ◽  
Takeshi Kuboyama ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Coupling Reaction ◽  
Radical Cyclization ◽  
Critical Coupling ◽  
Efficient Manner ◽  
Complete Control ◽  
Highly Efficient ◽  
Indole Synthesis

Stereocontrolled total synthesis of (+)-vinblastine (1) has been achieved using a novel radical-mediated indole synthesis developed in our laboratories. The isothiocyanate 18, prepared readily from quinoline 17, underwent a facile addition of the malonate anion to give 19. The o-alkenylthioanilide 19 was then converted to indole 20 by radical cyclization and protection. (−)-Vindoline (2) was prepared from this key intermediate 20 in a highly efficient manner. The indole core of the 11-membered intermediate 3 was constructed similarly from quinoline. The critical coupling reaction between 2 and the chloroindolenine derived from 3 proceeded with complete control of stereochemistry to give the desired product 66 in 97 % yield, which could be successfully converted to (+)-vinblastine (1).

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).

Peroxide-Mediated Oxidative Radical Cyclization to the Quinazolinone System: Efficient Syntheses of Deoxyvasicinone, Mackinazolinone and (±)-Leucomidine C

Synthesis ◽  
2020 ◽  
Author(s):  
Luis D. Miranda ◽  
Jazmín García-Ramírez
Keyword(s):  
Natural Products ◽  
Free Radical ◽  
Total Synthesis ◽  
Radical Cyclization ◽  
Oxidative Cyclization ◽  
Dicumyl Peroxide ◽  
Cyclization Process ◽  
Radical Cascade ◽  
Oxidative Radical Cyclization

AbstractAn efficient protocol for obtaining fused quinazolinones through an oxidative free-radical cyclization under metal- and tin-free conditions is described. The oxidative cyclization of various N-3-ω-iodoalkyl derivatives to provide tricyclic systems using dicumyl peroxide as the sole reagent is studied. The method then is employed for the syntheses of 5-, 6-, and 7-membered fused quinazolinone analogues, including the natural products deoxyvasicinone and mackinazolinone. A xanthate-based oxidative radical cascade addition/cyclization process that allows the production of new menthol- and testosterone-quinazolinone conjugates, as well as the first total synthesis of leucomidine C, are also reported.

scholarly journals Total Synthesis of Oxepin and Dihydrooxepin Containing Natural Products

Synthesis ◽  
2021 ◽  
Author(s):  
Thomas Magauer ◽  
Kevin Rafael Sokol
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Natural Product ◽  
Radical Cyclization ◽  
Sigmatropic Rearrangement ◽  
Natural Product Synthesis ◽  
Synthetic Methods ◽  
Acid Catalyzed ◽  
Metal Catalyzed ◽  
Key Steps

AbstractThe construction of oxepin and dihydrooxepin containing natural products represents a challenging task in total synthesis. In the last decades, a variety of synthetic methods have been reported for the installation of these structural motifs. Herein, we provide an overview of synthetic methods and strategies to construct these motifs in the context of natural product synthesis and highlight the key steps of each example.1 Introduction2 Oxepin Natural Products3 Dihydrooxepin Natural Products3 Brønsted or Lewis acid Catalyzed Cyclization3.2 Radical Cyclization3.3 Substitution and Addition Cyclization3.4 Sigmatropic Rearrangement3.5 Oxidative Methods3.6 Transition Metal Catalyzed Cyclization4 Summary

scholarly journals Fischer indole synthesis applied to the total synthesis of natural products

RSC Advances ◽  
2017 ◽  
Vol 7 (83) ◽  
pp. 52852-52887 ◽  
Author(s):  
Majid M. Heravi ◽  
Sahar Rohani ◽  
Vahideh Zadsirjan ◽  
Nazli Zahedi
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Biologically Active ◽  
Crucial Step ◽  
Fischer Indole Synthesis ◽  
Indole Synthesis ◽  
Active Natural

In this review, we are trying to underscore the application of FIS in one of the crucial step of indole construction in the total synthesis of biologically active natural products.

Application of Dess-Martin oxidation in total synthesis of natural products

2020 ◽  
Vol 17 ◽  
Author(s):  
Majid M. Heravi ◽  
Tayebe Momeni ◽  
Vahideh Zadsirjan ◽  
Leila Mohammadi
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Selective Oxidation ◽  
Secondary Alcohols ◽  
Aldehydes And Ketones

: 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.

scholarly journals Non-Enzymatic Desymmetrization Reactions in Aqueous Media

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 720
Author(s):  
Satomi Niwayama
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Functional Groups ◽  
Organic Compounds ◽  
Recent Progress ◽  
Aqueous Media ◽  
Building Blocks ◽  
Organic Reactions ◽  
Environmentally Benign ◽  
Enzymatic Desymmetrization

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.

Total synthesis: the structural confirmation of natural products

2021 ◽  
Vol 57 (27) ◽  
pp. 3307-3322
Author(s):  
Debobrata Paul ◽  
Ashis Kundu ◽  
Sanu Saha ◽  
Rajib Kumar Goswami
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Feature Article

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

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