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Journal ArticleDOI

Enaminones: versatile intermediates for natural product synthesis*

30 Jun 1999-Pure and Applied Chemistry (International Union of Pure and Applied Chemistry)-Vol. 71, Iss: 6, pp 979-988
TL;DR: In this article, an overview of the chemistry of enaminones and related compounds containing the structural unit N-CaC-Z (Za COR, CO2R, CN, NO2, S O 2Ar, etc.).
Abstract: Efforts in our laboratories to devise a general approach to the synthesis of alkaloids focus on the versatile reactivity of enaminones and related compounds containing the structural unit N-CaC-Z (Za COR, CO2R, CN, NO2 ,S O 2Ar, etc.). This lecture presents an overview of our research with these useful building blocks. Themes to be elaborated include chemo- selectivity and diastereoselectivity in reactions of enaminones, and the challenge of controlling absolute stereochemistry.

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Citations
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Journal ArticleDOI
TL;DR: In this article, a series of enamino ketones containing a (2-hydroxynaphthalen-1-yl)methyl or 2-hydroxybenzyl substituent in the α position with respect to the carbonyl were obtained.
Abstract: The reactions of 2-perfluoroacyl-1H-benzo[f]chromenes and 6,7-dimethyl-3-trifluoroacetyl-4H-chromene with primary aliphatic amines and ammonia afforded a series of enamino ketones containing a (2-hydroxynaphthalen-1-yl)methyl or 2-hydroxybenzyl substituent in the α-position with respect to the carbonyl group. These reactions involved opening of the pyran ring, which followed aza-Michael addition as the initial step. The obtained enamino ketones were found to exist in DMSO solution as single E isomers.

8 citations

Journal ArticleDOI
TL;DR: An investigation of the unique reactivity of these boron-based heterocycles has unveiled their underexplored potential as valuable building blocks and intermediates for organic synthesis.

7 citations

Journal ArticleDOI
TL;DR: In this article, the three possible tautomers of eneminones were fully optimized at several theoretical levels including B3LYP with the 6-31+G(d,p), 6-311++G(D,p) and aug-cc-pVDZ basis sets.
Abstract: Problem statement: Hydrogen bonding has a vital rule to unrevealed the nature of many different interactions both in gas phase and condensed media thus it is one of the most important concepts in chemistry. Enaminoes with their ability to form intrahydrogen bonded cheated rings represent one of the suitable compounds to study such concept. Approach: The three possible tautomers of eneminones were fully optimized at several theoretical levels including B3LYP with the 6-31+G(d,p), 6-311++G(d,p) and aug-cc-pVDZ basis sets as well as MP2/6-311++G(d,p) level of theory. Then a search for the possible transition state between the two most stable tautomers; the ketamine and the enolimine was done at the B3LYP/6-311++G(d,p) level of theory. Results: The ketamine is the most stable while the diketo is the less stable within the tautomeric mixture and the proton transfer occurs through a transition state that is energetically resemble the enolimine tautomer. Conclusion: The interconversion of the tautomers is preferable in the enolimine → ketamine direction.

7 citations


Cites background from "Enaminones: versatile intermediates..."

  • ...They are typical push-pull systems in which the amine group pushes and the carbonyl pulls electron density and have the ability to function both as ambident nucleophiles and as ambident electrophiles (Michael et al., 1999; Almazroa1 et al., 2004; Ruffino and Zanetti, 2009)....

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Journal ArticleDOI
TL;DR: In this article, an enamine-controlled hydroacylation of alkynes using a rhodium(I)/dppe catalyst system was described, which was highly selective, forming the linear enaminone products as single regioisomers in all examples.

7 citations

Journal ArticleDOI
TL;DR: Alu minu m phosphate (AlPO4) was used in this paper for condensation of 1,3-ketoesters with primary amines under free solvent conditions.
Abstract: Alu minu m phosphate (AlPO4) efficiently catalyzed the condensation of 1,3-ketoesters with primary amines under free solvent conditions. The catalyst has been prepared and characterized by powder XRD and FT-IR studies. The AlPO4 synthesis was performed in water at roo m temperature fro m AlCl3 and H3PO4 in the presence of ammonia solution. Resultant material showed good catalytic efficiency in condensation of 1,3-ketoesters with primary amines using a domestic micro wave oven with no solvent. The reaction was complete in 7 min to afford β-enamino esters in a high yield and high selectivity.

7 citations


Cites background from "Enaminones: versatile intermediates..."

  • ...Introduction β-enaminones are important intermediates in the synthesis of natural p roducts[1] and heterocyclic compounds[2,3] ....

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References
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BookDOI
01 Jan 1991
TL;DR: In this paper, the total synthesis of amaryllidaceae alkaloids has been studied using radical cyclization reactions in total syntheses of naturally occurring indole alkaloid.
Abstract: Chapter headings. Carbon-13 and proton NMR shift assignments and physical constants of diterpenoid alkaloids. Supercritical fluid extraction of alkaloids. Recent advances in the total synthesis of amaryllidaceae alkaloids. Applications of radical cyclization reactions in total syntheses of naturally occurring indole alkaloids.

1,263 citations

Book
29 Jun 1993
TL;DR: This paper presents the first total Synthesis of several Natural Products Based On Alkyne-Co2(Co2)6 Complexes, and discusses the design and synthesis of Cooperative "Pinwheel" Fluorescent Sensors, and the application of Silicon-Ass Intramolecular Cross-Coupling.
Abstract: Chapter 1. The Total Synthesis Of Luzopeptins. Chapter 2. Synthesis of Geldanamycin Using Glycolate Aldol Reactions. Chapter 3. From Methylene Bridged Glycoluril Dimers To Cucurbit[N]Uril Analogs With Some Detours Along The Way. Chapter 4. Application Of Silicon-Assisted Intramolecular Cross-Coupling In Total Synthesis Of (+)-Brasilenyne. Chapter 5. Samarium(II) Promoted Ketyl Olefin Cyclizations Applied To The Total Syntheses Of (-)-Steganone And (+)-Isoschizandrin. Chapter 6. The Synthesis Of Polycavernoside A. An Example Of Conformationally Guided Macrolactonization. Chapter 7. First Total Synthesis Of Several Natural Products Based On Alkyne-Co2(Co)6 Complexes. Chapter 8. Total Synthesis Of Myriaporones 1, 3, and 4. Chapter 9. Adventures In Natural Product Synthesis: From Deep Sea Sponge To Pilot Plant. The Large Scale Total Synthesis Of The Marine Natural Product (+)-Discodermolide. Chapter 10. Synthesis Of Aprepitant. Chapter 11. Total Synthesis And Mechanism Of Action Studies On The Antitumor Alkaloid,(-)-Agelastatin A. Chapter 12. Design And Synthesis of Cooperative "Pinwheel" Fluorescent Sensors. Chapter 13. Functionalization Of Pyridines And Thiazoles Via The Halogen-Dance Reaction, Application To The Total Synthesis Of Caerulomycin C And WS75624 B. Chapter 14. Diastereoselective Intramolecular 4+3 Cycloaddition And An Enantioselective Total Synthesis Of (+)-Dactylol.

175 citations