A Novel Reaction for Annulation onto α,β-Unsaturated Ketones: W(CO)5·L Promoted Exo- and Endo-Selective Cyclizations of ω-Acetylenic Silyl Enol Ethers Prepared by 1,4-Addition of Propargyl Malonate to Enones was written by Iwasawa, Nobuharu;Maeyama, Katsuya;Kusama, Hiroyuki. And the article was included in Organic Letters in 2001.Quality Control of Diethyl 2-(prop-2-yn-1-yl)malonate This article mentions the following:
Tungsten carbonyl catalysts promoted five- and six-membered ring annulations onto α,β-unsaturated ketones via cyclizations of acetylenic silyl enol ether intermediates. Thus, 1,4-addition of di-Et propargylmalonate to α,β-unsaturated ketones, e.g. cycloalkenones I (0-3) or PhCOCH:CHR1 (R1 = Ph, Me), in the presence of silyl triflates gave siloxy enynes, e.g. II (R1Si = Me3CSiMe2, i-Pr3Si) and siloxyhepenynes III, in good yield. W(CO)5·THF and W(CO)6 catalyzed photochem. cyclization of these intermediates gave either exo-cyclized products, e.g. methylenecyclopentanes IV and V, or endo-cyclized products, e.g. bicyclic ketones VI and benzoylcyclohexenes VII, in good yields simply by changing the reaction solvent. In the experiment, the researchers used many compounds, for example, Diethyl 2-(prop-2-yn-1-yl)malonate (cas: 17920-23-9Quality Control of Diethyl 2-(prop-2-yn-1-yl)malonate).
Diethyl 2-(prop-2-yn-1-yl)malonate (cas: 17920-23-9) belongs to esters. Esters typically have a pleasant smell; those of low molecular weight are commonly used as fragrances and are found in essential oils and pheromones. Esterification is the general name for a chemical reaction in which two reactants (typically an alcohol and an acid) form an ester as the reaction product. Esters are common in organic chemistry and biological materials.Quality Control of Diethyl 2-(prop-2-yn-1-yl)malonate
Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics