Алкилирование енаминов, бета-дикетонов и енаминокетонов

bichromophoric systems.Possible reaction mechanisms are considered.The origin of another major product, 11, generated by irradiation of 9f with Vycor-filtered light, is also discussed.

Regioselective control of N-aryl enaminone alkylation

Denise Dugat; Daniel Gardette; Jean-Claude Gramain; Bertrand Perrin

Source details: Bull.Soc.Chim.Fr. 1994, 131 : 1 66-70.

Document type: Journal

CODEN: BSCFAS

Language: EN

CNR: 5851695

Abstract

The regioselectivity of the C-alkylation of unsubstituted N-aryl enaminones prepared from cyclohexane-1,3-dione may be controlled by the nature of the base used.Our results indicate that monoalkylation is completely regioselective; lithium diisopropylamide leads to α’-alkylated compounds while lithium bis(trimethylsilyl)amide affords γ-alkylated products.In contrast, alkylation of α’- or γ-substituted compounds always occurs in the α’-position regardless of the base.

Regiospecificity and Regioselectivity of the Alkylation, Acylation, Sulfenylation and Sulfonylation of Pyrrolidine Enaminones

Thomas Burgemeister; Gerd Dannhardt; Ernst Eibler; Brigitte Paulus; Klaus Ziereis

Source details: Arch.Pharm.(Weinheim Ger.) 1988, 321 : 345-348.

Document type: Journal

CODEN: ARPMAS

Language: GE

CNR: 5807249

Abstract

Different methods to modify a pyrrolidine enaminone regiospecifically or regioselectively at the N- and C-atom, respectively, are described.All compounds have been isolated and characterized, in case of the alkylation reactions the ratio of regioisomers is determined by HPLC.NOE experiments are performed in order to prove the configuration of some adducts.

Reactivity of N-substituted enaminones with unsaturated carbonyl compounds

Esther Caballero; Blanca Madrigal; Manuel Medarde; Pilar Puebla; Zoila Honores; et al.

Source details: Ach.Mod.Chem. 1998, 135 : 4 457-474.

Document type: Journal

CODEN: ACMCEI

Language: EN

CNR: 6101721

Abstract

The reactivity of enaminones of 2-aminoethanol and 2-aminoethanothiol towards polyelectrophilic reagents has been studied.A brief overview of our previous results with this enaminones, which allowed us to describe new synthesis of fused heterocycles, is included. In the present work, only the formation of C-C bond is a common feature of the reaction, to produce derivatives or simple heterocycles.Although no fused heterocycles were obtained, the reaction products have complex functionalization which will allow further cyclization to such a class of polyfused systems.

Reactions between Enaminones and Enones. Part 2. C versus N-Alkylation with Cyclohex-2-enone. Structure Confirmation by Reduction of a Dienaminone Derivative of Dehydrated Dimedone Dimer

Ibrahim Chaaban; John V. Greenhill; Mohamed Ramli

Source details: J.Chem.Soc.Perkin Trans.1 1981, 3120-3124.

Document type: Journal

CODEN: JCPRB4

Language: EN

CNR: 5625982

Abstract

Primary and secondary enaminones derived from cyclohexane-1,3-dione, dimedone, and acetylacetone react with cyclohexenone to give exclusively C-alkylated derivatives.In every case the products form carbinolamines which exist as 1-hydroxy-2-azacyclo[3.3.1]nonenes.This was confirmed in some examples by formation of an extra ring between nitrogen and oxygen.A series of dienaminones were prepared from 2-(5,5-dimethyl-3-oxocyclohex-1-enyl)-5,5-dimethylcyclohexane-1,3-dione and one of these was reduced to give an azanonene identical with that from C-alkylation.