From acetylenic alcohols

Unsymmetrical trans vinyl halides have been prepared from acetylenic alcohols by Corey and co-workers (as illustrated in the accompanying formulation) in connection with their synthesis of farnesol and Gecropia juvenile hormone. Several syntheses of vinyl halides (with... 

A shift from allenes to acetylenic products formed from acetylenic alcohols in which trifluoro-methyl groups are replaced by difluoromethyl groups can be explained in terms of lowering the positive character of the terminal acetylenic carbon atom, thus retarding the nucleophilic attack of fluorine at this position.56... 

H. Laas, A. Nissen, and A. Niirrenbach, A simple synthesis of 3 i7-indoles starting from acetylenic alcohols, Synthesis, 1981, 958-959. 

The method has been extended to the preparation of difunctional compounds. Dihalides Including the mixed variety are formed in 90 to 98% yields. Primary unsaturated bromides of the type RCH=CHCH,Br have been formed from the corresponding alcohols by the action of phosphorus tribromide and pyridine at a low temperature without any apparent rearrangement. However, the corresponding secondary-carbinol system, RCHOHCH=CH is very susceptible to allylic isomerization. The formation of a, -acetylenic bromides from acetylenic alcohols and phosphorus tribromide is common (40-70%). An acetylenic-allenic isomerization has been observed, viz.,... 

Unsaturated ethers, RCH = CHCH20CHj, have been prepared from the corresponding allylic alcohols and dimethyl sulfate in the presence of sodium amide (60-80%). Acetylenic ethers are made in a similar manner from acetylenic alcohols. The hydroxyethylation of phenols with ethylene sulfite or ethylene carbonate appears to be a promising reaction for the formation of hydroxy ethers of the type ROCH,CHjOH. ... 

Rupe, H., Kambli, E. Unsaturated aldehydes from acetylene alcohols. Helv. Chirm. Acta 1926, 9, 672. 

Pyridines.—Synthesis. A full report on the synthesis of pyridones from acetylenic alcohols and N-cyanopyrrolidine, noted in Volume 7 of Aromatic and Heteroaromatic Chemistry , has appeared.2-Imino-l,2-dihydropyridines (1)... 

CYCLIZATION OF SOME 1,3-BUTADIENES PRODUCED FROM ACETYLENIC ALCOHOLS OF THE PROPARGYL TYPE... 

This is an example of an acetylenic alcohol. It is prepared from acetone by the following series of reactions ... 

A mixture of 0.30 mol of the acetylenic tosylate (prepared according to the general method described in VlII-3, Exp. 3 from the corresponding acetylenic alcohol, which was prepared from HC=CHgBr and CgHi3CH=0 in THF, as described in Ref. l)and 100 ml of dry acetone was added to a solution of 0.40 mol of anhydrous... 

A mixture of 0.10 mol of the acetylenic alcohol, 0.12 mol of triethylamine and 200 ml of dichloromethane (note 1) was cooled to -50°C. Methanesulfinyl chloride (0.12 mol) (for its preparation from CH3SSCH3, (08300)30 and chlorine, see Ref. 73) was added in 10 min at -40 to -50°0. A white precipitate was formed immediately. After the addition the cooling bath was removed and the temperature was allowed to rise to -20°0, then the mixture was vigorously shaken or stirred with 100 ml of water. The lower layer was separated off and the aqueous layer was extracted twice with 10-ml portions of CH2CI2. The combined solutions were dried over magnesium sulfate and concentrated in a water-pump vacuum (note 2). The yields of the products, which are pure enough (usually 96%) for further conversions, are normally almost quantitative. 

Alcohols are stronger acids than acetylene and so the position of equilibrium lies to the left Methoxide ion is not a strong enough base to remove a proton from acetylene... 

Until World War 1 acetone was manufactured commercially by the dry distillation of calcium acetate from lime and pyroligneous acid (wood distillate) (9). During the war processes for acetic acid from acetylene and by fermentation supplanted the pyroligneous acid (10). In turn these methods were displaced by the process developed for the bacterial fermentation of carbohydrates (cornstarch and molasses) to acetone and alcohols (11). At one time Pubhcker Industries, Commercial Solvents, and National Distillers had combined biofermentation capacity of 22,700 metric tons of acetone per year. Biofermentation became noncompetitive around 1960 because of the economics of scale of the isopropyl alcohol dehydrogenation and cumene hydroperoxide processes. 

The isophytol side chain can be synthesized from pseudoionone (Fig. 5) using chemistry similar to that used in the vitamin A synthesis (9). Hydrogenation of pseudoionone (20) yields hexahydropseudoionone (21) which can be reacted with a metal acetyUde to give the acetylenic alcohol (22). Rearrangement of the adduct of (22) with isopropenyknethyl ether yields, initially, the aHenic ketone (23) which is further transformed to the C g-ketone (24). After reduction of (24), the saturated ketone (25) is treated with a second mole of metal acetyUde. The acetylenic alcohol (26) formed is then partially hydrogenated to give isophytol (14). 

Tlie addition reactions of allylic and acetylenic alcohols produce compounds resulting from rearrangements [16, 17] (equation 7). 

Acetylenic alcohols can be obtained using another technique from bromacety-lene with subsequent action of butyllithium and carbonyl compound (Scheme 63). 

Enyne metathesis starting either from acetylenic boronates and homoallylic alcohols [104a,c] or from propargyl alcohols and allylboronates [104b] has recently been described. The resulting boronated dienes can be converted to allenes or cycloaddition products. The cross metathesis of vinylcyclopropyl-boronates directed toward the total synthesis of natural products has very recently been investigated by Pietruszka et al. [104d]. 

Vinyl acetate is polymerized to poly(vinyl acetate), (PVAc), which finds use in adhesives and water-based paints. Some PVAc is hydrolyzed (reacted with water) to poly(vinyl alcohol) (PVA) for textile sizing, adhesives, and paper coatings. A substantial amount of U.S.-produced vinyl acetate is exported. Prior to 1970, almost all vinyl acetate was made from acetylene. Now none of it is. 

Chiral lactones were also obtained by cyclocarbonylation of chiral acetylenic alcohols with Pd and thiourea (H2NCSNH2) (Scheme 32). No loss in chirality was observed, but large amounts of Pd and thiourea were used (10 mol %) since the catalyst deactivates by forming metal particles. The catalytic precursor (Pdl2 > PdCl2) and the ratio of thiourea to Pd were very important, thiourea being necessary for this reaction. The active species was supposed to be [Pd(thiourea)3l]I, which forms in situ from [Pd(thiourea)4]l2 and [Pd(thiourea)2]l2. It had to be a partially dissociated species since [Pd(thiourea)4](Bp4)2 was inactive [121]. 

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