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

Abstract

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). * For communication XXI, see [1]. Base-catalyzed intramolecular cyclizations of -(2-propynyloxy)-[2-8], -(2-propynylsulfanyl)-[9], and -(2-propynylamino)alkan-1-ols [10,11], as well as of their 2-haloallyl analogs [4,5,9], have been studied in sufficient detail. Such cyclizations (which involve intramolecular nucleophilic addition of functional group at the acetylenic triple bond) are among the most widespread reactions leading to five-, six-, or seven-membered heterocycles containing one or two heteroatoms (N, O, S) [8,12, 13]. However, in the series of -(2-propynyloxy)alkan-1-ols, only 2-(2-propynyloxy)ethanol and its simplest derivatives R 1 C CC(R 2 )(R 3 )OCH(R 4 )CH(R 5 )OH (R 1 = R 2 = R 3 = R 4 = R 5 = H [3, 4, 7]; R 1 = R 2 = R 3 = R 4 = H, R 5 = Me, Ph; R 1 = R 2 = R 3 = R 5 = H, R 4 = Ph; R 1 = R 2 = R 3 = H, R 4 = R 5 = Me [3, 6]; R 1 = R 2 = R 4 = R 5 = H, R 3 = Me [7]; R 1 = R 4 = R 5 = H, R 2 = Me, R 3 = Ph [8]; R 1 = R 2 = R 4 = H, R 3 = R 5 = Me [3, 6, 7]; R 1 = Me, R 2 = R 3 = R 4 = R 5 = H [7]), 3-(2-propynyloxy)propan-1-ol [5], 2-(2-propynyloxy)cyclopentanol [7], and 2-(2-propynyloxy)cyclohexanol [3, 6, 7] were studied.Obviously, introduction of additional reaction centers, e.g., olefinic fragments with qualitatively different chemical natures of the double carbon-carbon bonds (specifically vinyloxy and allyloxy groups), into (2-propynyloxy)alkanol molecules should strongly extend the synthetic potential of both initial alkanols [1][2][3][4][5][6][7][8]12] and their cyclization products [1,8,14], as well as the range of their useful properties and the scope of practical application. Known representatives of this class of compounds are used in various fields (see, e.g., references in [1]), including the synthesis of dendrimers, dienes, -hydroxy and -oxo acids, -hydroxymethyl ketones, , '-dihy...

Vinyl Ethers Containing an Epoxy Group: XXIII. Reactions of Alkynylmagnesium Bromides with Glycidol Ethers: Synthesis and Thermal Transformations of 1-[2-( Vinyloxy)ethoxy]- and 1-(Allyloxy)-5-hexyn-2-ols, -5-phenyl-4-pentyn-2-ols, and -3-bromo-2-propanols

“…The epoxy ring opened at the side of the most hydrogenized carbon affording compounds with a secondary hydroxy group [41]. These results are in agreement with our [1,37,38] and other published data [10,42] showing that the basecatalyzed opening of the oxirane ring occurs as a rule with the attack of the nucleophile on the least substituted carbon atom (b-opening); in the terminal oxiranes this is the methylene carbon atom (cleavage of the OCH 2 bond).…”

“…In extension of our systematic investigations in the area of the chemistry of unsaturated glycidol ethers [1,DMITRIEVA et al 37,38] we studied for the first time reactions of 2-[2-(vinyloxy)ethoxy]methyl-(Ia) and 2-(allyloxymethyl)-(Ib) oxiranes with organomagnesium reagents, in particular, with alkynylmagnesium halides: 2-propynylmagnesium bromide (IIa) and phenylethylylmagnesium bromide (IIb), aiming also on developing a preparation procedure for new representatives of polyfunctional acetylene alcohols: 1-[2-(vinyloxy)ethoxy]-(IIIa and IVa) and 1-(allyloxy)-(IIIb and IVb) -5-hexyn-2-ols and -5-phenyl-4-pentyn-2-ols, promising monomers and intermediate products for organic synthesis, also for the synthesis of heterocyclic structures [1,38].…”

“…The alkynols combining the properties of the three most important classes of organic compounds (alcohols [19], acetylenes [20], and CH-acids when the compounds contained fragments CºCH and/or CH 2 CºC [21,22]) are valuable intermediates in preparation of a lot of synthetically and commercially significant products (chemicals for agriculture, drugs, and fragrant substances [9,23]). They are widely used in the synthesis of functionalized acetylene alcohols and diols [1,24], heterocycles, including derivatives of furan [25], pyran [26], pyrrole [27], indole [28], pyrazole [29], 2,3-dihydropyridine, pyridine [30], benzazepine-1,5-dione [31], thiophene [32], various allene systems [20,23,24,33], in particular, allenols that are invaluable monomers and key building blocks [23,24,34], naturally occurring compounds: indolizine [35] and quinolizine [36] alkaloids, etc.…”

“…IR spectrum, cm 1 1-[2-(Vinyloxy)ethoxy]-5-phenyl-4-pentyn-2-ol (IVa) and 1-(allyloxy)-5-phenyl-4-pentyn-2-ol (IVb) ( Table 2). a.…”

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

“…The oxirane ring in vinylox and its analogs is easily opened by various nucleophilic reagents [7,14,15,[52][53][54][55][56][57][58][59][60][61][62][63][64] with retention of the vinyloxy group, representing a new general approach to the synthesis of the most widely varied functionalized vinyl ethers. After treatment with organyltrialkoxysilanes the adduct of vinylox with diethanolamine 3 [63] gives "anchor" silatranes 4 unusually readily and with almost quantitative yields [64].…”