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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TL;DR: In this paper, an efficient strategy for the synthesis of enaminones by the nucleophilic addition of N-heterocycles such as indole and imidazoles onto electronically bias alkynones under mild reaction conditions is described.
Abstract: An efficient strategy for the synthesis of $$\upalpha $$
,
$$\upbeta $$
-unsaturated enaminones by the nucleophilic addition of N-heterocycles such as indole and imidazoles onto electronically bias alkynones under mild reaction conditions is described. Key feature of this reaction is the chemoselective addition of N-heterocycles onto ynones without affecting the $$1^{\mathrm{o}}$$
amino groups (aromatic and aliphatic) of 5-aminoindole and tryptamine. The stereochemistry of the products was controlled by the tuning of reaction time. The mechanism of the reaction involves the Michael type addition of N-heterocycles on ynones via allene formation.
4 citations
TL;DR: In this article, a tridentate ligand coordinated by oxygen atoms of carbonyl and methoxy groups as well as the nitrogen atom of the amide group was obtained for 2-anilinomethylidene-5,5-dimethyl-cyclohexane-1,3-dione.
Abstract: [Cu(L)2] (1), [Co(L)2] (2), [Ni(L)2]·H2O (3) complexes where L is 2-{[(2-methoxyphenyl)amino]methylene}-5,5-dimethyl-cyclohexane-1,3-dionate are synthesized. Single crystals of complexes 1-3 are obtained. According to X-ray crystallographic data, in the Co and Ni complexes, a coordination polyhedron N2O4 is a distorted octahedron, and in the Cu complex, N2O2 is a distorted square. L is a tridentate ligand coordinated by oxygen atoms of carbonyl and methoxy groups as well as the nitrogen atom of the amide group. The cytotoxic properties of 2-{[(2-methoxyphenyl)amino]methylene}-5,5-dimethyl-cyclohexane-1,3-dione and respective complexes are studied on the Hep2 cell line (human laryngeal carcinoma). The compounds are shown to not exhibit cytotoxic properties in the studied concentration range (1-50 μM). Antibacterial, protistocidal, and fungistatic properties of HL, its structural analogue 2-anilinomethylidene-5,5-dimethylcyclohexane-1,3-dione (HL1), and complexes on their base are also studied. The antibacterial activity of HL and [Co(L1)2(C2H5OH)2] against S. aureus, of HL1 and [Co(L)2] against E. coli is revealed within 25-30% of the activity of reference drugs (ciprofloxacin, furazolidone). The [Ni(L1)2(C2H5OH)2] complex is found to have a pronounced protistocidal activity. Furthermore, the behavior of the [Ni(L)2]·H2O complex in phosphate buffered saline is analyzed at storage times t = 0 h, 24 h, 48 h and also in an aqueous solution at different pH values.
4 citations
TL;DR: Enamination of a wide variety of primary amines was successfully described with excellent chemo-selectivity in the presence of catalytic amounts of β-cyclodextrin in water under mild conditions.
Abstract: Enamination of a wide variety of primary amines was successfully described with excellent chemo-selectivity in the presence of catalytic amounts of β-cyclodextrin in water under mild conditions. Aliphatic amines also reacted efficiently to produce the corresponding enaminones.
4 citations
4 citations
TL;DR: In this paper, an efficient one-pot synthesis of vinylogous carbamates was reported starting from alkyl azides by using NH 4 Cl/Zn dust.
3 citations
References
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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
40 citations