275815-89-9Relevant academic research and scientific papers
Coupling-isomerization synthesis of chalcones
Braun, Roland U.,Ansorge, Markus,Mueller, Thomas J. J.
, p. 9081 - 9094 (2007/10/03)
The Sonogashira coupling of electron-deficient (hetero)aryl halides 1 and (hetero)aryl or alkenyl 1-propargyl alcohols 2 does not terminate at the stage of the expected internal propargyl alcohols, but rather gives rise to the formation of α,β-unsaturated ketones 3 with a variety of acceptor substituents. This new domino reaction, a coupling-isomerization reaction (CIR), can be rationalized as a sequence of rapid Pd/Cu-catalyzed alkynylation followed by a slow amine-base-catalyzed propargyl alcohol-enone isomerization. Performing the CIR in deuterated protic solvents or with a selectively deuterated propargyl alcohol revealed that the base-catalyzed isomerization step proceeds through a formal 1,3-H shift with minimal H/D exchange with the surrounding solvent. Additionally, 19F NMR kinetic measurements on the isomerization step with the fluorinated propargyl alcohol 4r support the mechanistic rationale.
An unexpected coupling-isomerization sequence as an entry to novel three-component-pyrazoline syntheses
Mueller, Thomas J.J.,Ansorge, Markus,Aktah, Daniel
, p. 1253 - 1256 (2007/10/03)
A novel retrosynthetic approach to 3,5-diaryl-2-pyrazolines is provided by a three-component, one-pot reaction initiated by a palladium/copper- catalyzed cross-coupling (see scheme). The initially formed enone cyclocondenses in situ with the hydrazine to
A novel three-component one-pot pyrimidine synthesis based upon a coupling-isomerization sequence
Muller, Thomas J. J.,Braun, Roland,Ansorge, Markus
, p. 1967 - 1970 (2007/10/03)
(Equation presented) 246-Tri(hetero)aryl-substituted pyrimidines can be readily synthesized in a three-component one-pot process based upon a coupling-isomerization sequence of an electron-poor (hetero)aryl halide and a terminal propargyl alcohol subseque
