91324-56-0Relevant academic research and scientific papers
Vinyl ethers containing an epoxy group: XXII. Synthesis and base-catalyzed transformations of 1-(allyloxy)- and 1-[2-(vinyloxy)ethoxy]-3-(2-propynyloxy) propan-2-ols
Dmitrieva,Nikitina,Albanov,Nedolya
, p. 1430 - 1444 (2005)
Reactions of 2-(allyloxymethyl)- and 2-[2-(vinyloxy)ethoxy]methyloxiranes with 2-propynol (-3 wt % of t-BuOK, 75-85°C, 5-10 h) lead to formation of new 1-organyloxy-3-(2-propynyloxy)propan-2-ols (yield 65-95%). On heating to 45-100°C in the presence of bases (KOH, t-BuOK), 1-allyloxy- and 1-[2-(vinyloxy)ethoxy]-3-(2-propynyloxy)propan-2-ols are transformed into the corresponding 2-vinyl-1,3-dioxolane, 6-methyl-2,3-dihydro-1,4-dioxine, 6-methylene-1,4-dioxane, and 2,3-dihydro-5H-1,4-dioxepine derivatives, whose yield and ratio strongly depend on the solvent nature, catalyst, and substituent at the hydroxy group. 2-Vinyl-1,3-dioxolane and 6-methyl-2,3-dihydro-1,4- dioxine derivatives are formed as the major products (yield 70-99%) in the presence of t-BuOK in aprotic media (toluene, THF, DMSO) or in the absence of a solvent as a result of prototropic isomerization followed by intramolecular heterocyclization. Intramolecular nucleophilic cyclization of 3-(2-propynyloxy)propan-2-ols to 6-methylene-1,4-dioxane is the predominant process in water in the presence of KOH. In all cases, the fraction of 2,3-dihydro-5H-1,4-dioxepine derivatives among the cyclization products ranges from 0 to 5% (KOH) or to 14% (t-BuOK).
