Nucleophilic addition to acetylenes in superbasic catalytic systems: XVIII. Vinylation of phenols and naphthols with acetylene

Abstract

Phenols and naphthols react with acetylene in a superbasic system KOH-DMSO forming the corresponding aryl vinyl ethers in up to 80% yields. * For communication XVII, see [1].Aryl vinyl ethers compared with aliphatic analogs are more stable against hydrolysis and are more reactive in the radical polymerization. They are highly reactive building blocks for organic synthesis. The pioneering research in this field was carried out by the scientific school of A.V. Kalabina [2-4] who widely used aryl vinyl ethers for the preparation of polymer materials [5][6][7][8][9][10][11][12], in the diene synthesis [13][14][15][16], and also in the design of biologically active compounds, in particular, of insecticides and herbicides [17]. The chemistry of aryl vinyl ethers has been actively developed in the recent decades [18][19][20][21]. They were utilized for designing new polymer compositions [20,21], reagents for the chemical plant protection [22]. A high selectivity of aryl vinyl ethers was found at the ammetric titration of metal ions, in particular, of Ag(I) [23]. Vinyl ether of fluorescein was recommended as a highly sensitive fluorescent probe for organomercury compounds in cells and living bodies [24]. New methods of aryl vinyl ethers production are under development, among which the following are worth considering: catalytic reaction of phenols with various vinyl equivalents, e.g., vinyl halides [25, 26], vinylboronic acids [27, 28], tetravinyl-and tributyl-(vinyl)tin [29], vinyl esters of carboxylic acids [21, 30], and also the synthesis of aryl vinyl ethers from 2-phenylselenyl-ethanol [31-33] or 2-phenylsulfonylethanol [34] and phenols at treating with Mitsunobu reagent (diethyl ether of azodicarboxylic acidtriphenylphosphine). Recently a new two-stage method was patented of the production of aromatic vinyl ethers in a low yield (10-38%) involving vinylation of 2-aryloxyethanols (100 о С, 3-6 h, acetylene pressure 1.4 at, KОН-DMSO) with the formation of the corresponding 2-aryloxyethyl vinyl ethers followed by heating of the latter (130-140 о С, 6-10 h, DMSO) in the presence of double molar excess of KОН [35].The classic synthesis method of aryl vinyl ether through direct phenol vinylation with acetylene under the basic catalysis conditions not only conserves its importance but possesses obvious advantages before the mentioned procedures [21,[25][26][27][28][29][30][31][32][33][34][35] since it is atomeconomical, one-stage, and is based on a raw material of a large-scale production. Phenols add to acetylene in the presence of KОН at a high pressure (30-50 at) and a high temperature (180-200 о С) [2,[36][37][38][39][40].The aim of this study is the development of a technologically more convenient procedure of the synthesis of aryl vinyl ethers by vinylation of phenols and naphthols with acetylene in superbasic catalytic environment (alkali metal hydroxide-polar hydroxylfree solvent). The application of superbasic media in the acetylene chemistry made it possible to improve the most important reactions of nucleophili...

An Atom‐Economic Approach for Vinylation of Indoles and Phenols Using Calcium Carbide as Acetylene Surrogate

“…[16] On the other hand, aryl vinyl ethers serve as i) valuable intermediates in various reactions, [17] ii) precursors for polymeric materials, [18] and iii) as phenolic protecting groups [19] in organic synthesis. [31] However, the above mentioned methods for the synthesis of N-vinylpyrole and aryl vinyl ether have some drawbacks. An alternative method for N-vinylation of indoles involves the use of 1,2-dichloroethane in the presence of phase transfer catalyst.…”

Metal‐free Intermolecular Hydrophenoxylation of Aryl Alkynes

“…Significant progress in the intermolecular nucleophilic addition of alcohols onto alkynes by using base was made by Kondo, Knochel (Scheme , i), and Minidis . In 2015, Trofimov reported the base‐mediated reaction of phenols with acetylene (Scheme , ii). In 1998, Teles and co‐workers reported the formation of alkoxyalkanes and enol ethers by the direct addition of alcohols to alkynes by using cationic gold(I) .…”

Hydroalkoxylation of alkynes by a nitroxyl containing alcohol, 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl: synthesis of spin-labeled enol ethers

“…[25][26][27][28][29][30][31][32][33][34][35][36] Since the first synthesis of 4-vinyloxy-TEMPO, 24 no attempt to develop an expedient hydroalkoxylation of alkynes with 4-hydroxy-TEMPO has been undertaken. Meanwhile, having in mind that direct superbasecatalyzed hydroalkoxylation of alkynes with hydroxyl compounds has proved to be highly efficient, [37][38][39][40][41][42] we decided to revisit the vinylation of 4-hydroxy-TEMPO with various alkynes exploiting our expertise gained during the last decade.…”