40485-33-4Relevant academic research and scientific papers
A New General Synthesis of 2,2-Dialkyl-2,3-dihydro-4H-pyran-4-ones and Their Application for the in situ Preparation of Electron-Rich Dienes in Carbonyl-Alkyne Exchange Reactions with Acetylenes
Obrecht, Daniel
, p. 27 - 46 (2007/10/02)
The substituted 2,2-dialkyl-2,3-dihydro-4H-pyran-4-ones of type II and III have been prepared by acid-catalyzed cyclization of the corresponding substituted acetylenic ketones I in good to excellent yields (Scheme 1).These 2,2-dialkyl-2,3-dihydro-4H-pyran
53. Acid-Catalyzed Cyclization Rections of Substituted Acetylenic Ketones: A New Approach for the Synthesis of 3-Halofurans, Flavones, and Styrylchromones
Obrecht, Daniel
, p. 447 - 456 (2007/10/02)
Acetylenic acetals of type I (Scheme 1) and acetylenic ketones of type III (Scheme 1), 37 and 38 (Scheme 7) are versatile synthetic precursors for the synthesis of various heterocycles by acid-catalyzed cyclization reactions.By this way, substituted 3-halofurans of type II and IV (Scheme 1) and flavones and styrylchromones (Scheme 7) can be synthesized in good-to-excellent yields.The high degree of regioselectivity in the synthesis of the 3-halofurans (Scheme 4) is the result of the regioselective β-addition of HX (X = Cl, Br, I) to the acetylenic aldehyde and acetylenic ketone moieties.A possible mechanism is depicted in Scheme 5.Since 3-halofurans can easily be metalated and substituted, this approach constitutes a new synthesis of highly substituted furans.
