In 2019,Organic Chemistry Frontiers included an article by Beltran, Frederic; Andna, Lucile; Miesch, Laurence. Synthetic Route of C5H6O2. The article was titled 《Spirocyclization of keto-ynesulfonamides promoted by quaternary ammonium salts》. The information in the text is summarized as follows:
Spirocyclization of keto-ynesulfonamides R(CH2)2N(CCR1)Ts (R = 2-oxocyclopentyl, 5,5-dimethyl-2-oxocyclohexyl, 8-oxo-1,4-dioxaspiro[4.5]decan-7-yl, etc.; R1 = H, Ph, 2H-1,3-benzodioxol-5-yl, etc.) with quaternary ammonium salts was performed to access aza-spiro compounds, e.g., I. Exclusive E-configured 5-exo-dig compounds e.g., I were isolated from keto-ynesulfonamides substituted by an aryl- or a vinyl group, whereas 6-endo-dig compounds e.g., II were favored from terminal ynesulfonamides.Ethyl propiolate(cas: 623-47-2Synthetic Route of C5H6O2) was used in this study.
Ethyl propiolate(cas: 623-47-2) is a clear colorless to pale yellow liquid that is soluble in ethanol, ether and chloroform. It an important organic chemical raw material and pharmaceutical intermediate. Ethyl propargylate is obtained by oxidation of propargyl alcohol to propargylic acid followed by esterification.Synthetic Route of C5H6O2
Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics