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
作者:L. L. Dmitrieva、L. P. Nikitina、A. I. Albanov、N. A. Nedolya
DOI:10.1007/s11178-005-0362-0
日期:2005.10
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).
2-(烯丙氧基甲基)-和 2-[2-(乙烯基氧基)乙氧基]甲基环氧乙烷与 2-丙炔醇的反应(t-BuOK ∼ 3 wt %,75-85°C,5-10 小时)可生成新的 1-烯丙氧基-3-(2-丙炔氧基)丙-2-醇(产率 65-95%)。在碱(KOH、t-BuOK)存在下加热到 45-100°C 时,1-烯丙氧基和 1-[2-(乙烯氧基)乙氧基]-3-(2-丙炔氧基)丙-2-醇转化为相应的 2-乙烯基-1,3-二氧戊环、6-甲基-2、3-二氢-1,4-二氧杂环戊烷、6-亚甲基-1,4-二氧杂环戊烷和 2,3-二氢-5H-1,4-二氧杂环庚烷衍生物,其产率和比例主要取决于溶剂性质、催化剂和羟基上的取代基。2 乙烯基-1,3-二氧戊环和 6-甲基-2,3-二氢-1,4-二氧杂环庚烷衍生物的主要生成物(产率为 70-99%)是在无相介质(甲苯、四氢呋喃、二甲基亚砜)中有 t-BuOK 存在的情况下,或在无溶剂的情况下,通过原向异构化和分子内杂环化反应生成的。在有 KOH 存在的水中,3-(2-丙炔氧基)丙-2-醇分子内亲核环化为 6-亚甲基-1,4-二氧六环的过程占主导地位。在所有情况下,环化产物中 2,3-二氢-5H-1,4-二氧杂环庚烷衍生物的比例为 0%至 5%(KOH)或 14%(t-BuOK)。