Olefins acid addition

Olefinic acetals, preparation, 263 preparations listed in table 23, 268 a, S-01efinic acetals, preparation, 37 Olefinic acetylenes, addition of alcohols, 233, 266 alkylation, SO partial reduction, 46 preparatioh, 34, 39, 46, 48, 80 preparations listed in table 6, 84 Olefinic acids, addition, of halogen, 107... 

Polymerization of olefins such as styrene is promoted by acid or base or sodium catalysts, and polyethylene is made with homogeneous peroxides. Condensation polymerization is catalyzed by acid-type catalysts such as metal oxides and sulfonic acids. Addition polymerization is used mainly for olefins, diolefins, and some carbonyl compounds. For these processes, initiators are coordination compounds such as Ziegler-type catalysts, of which halides of transition metals Ti, V, Mo, and W are important examples. 

The elements of bromine azide have been added to steroid olefins. The addition can be rationalized as proceeding through a positive bromonium ion under the ionic conditions of Hassner and Boerwinkle (bromine plus sodium azide and hydrochloric acid in nitromethane-dichloromethane) or Ponsold (A-bromosuccinimide or A-bromoacetamide in chloroform contain-... 

In addition, several S/S ligands were also investigated for the asymmetric hydrogenation of olefins. In 1977, James and McMillan reported the synthesis of various disulfoxide ligands, which were applied to the asymmetric ruthenium-catalysed hydrogenation of prochiral olefinic acid derivatives, such as itaconic acid. These ligands, depicted in Scheme 8.16, were active to provide... 

Although thiolacetic acid additions are free-radical reactions (60), it was found recently that the addition to electron-poor olefins can be base catalyzed (61) (eqs. [14], [15]). Thus the (S)-(-) adduct is obtained with an e.e. of 54% when cyclohexenone is treated with thiolacetic acid in benzene in the presence of catalytic amounts of cinchonine. The reaction appears to be quite general, although very high e.e. s (>80%) have not yet been achieved. 

Copper-catalyzed monoaddition of hydrogen cyanide to conjugated alkenes proceeded very conveniently with 1,3-butadiene, but not with its methyl-substituted derivatives. The most efficient catalytic system consisted of cupric bromide associated to trichloroacetic acid, in acetonitrile at 79 °C. Under these conditions, 1,3-butadiene was converted mainly to (Z )-l-cyano-2-butene, in 68% yield. A few percents of (Z)-l-cyano-2-butene and 3-cyano-1-butene (3% and 4%, respectively) were also observed. Polymerization of the olefinic products was almost absent. The very high regioselectivity in favor of 1,4-addition of hydrogen cyanide contrasted markedly with the very low regioselectivity of acetic acid addition (vide supra). Methyl substituents on 1,3-butadiene decreased significantly the efficiency of the reaction. With isoprene and piperylene, the mononitrile yields were reduced... 

Also azide radicals generated by anodic oxidation of sodium azide in the presence of olefins afford in acetic acid additive dimers, products of allylic substitution and... 

A major concern in H2O2 oxidation is the alcohol/olefin chemoselectivity (Rao, 1991). This biphasic oxidation was initially developed for olefin epoxidations but with an (aminomethyl)phosphonic acid additive for high selectivity (Rudolph et al., 1997). Now, the removal of this additive has been found to significantly increase the rate and selectivity of alcohol oxidation. 

Frjedel-Crafts Reaction. Any organic reaction brought about by the catalytic action of anhydrous aluminum chloride or related, so-called Lewis acid type catalysts. Discovered in 1877 by C. Friedel and J.M. Crafts, who later uncovered most of the types of reaction such as substitution, isomerization, elimination, cracking, olefin polymerization, addition, etc. Commonly used to displace an aromatic hydrogen atom with an alkyl, aryl or acyl chain... 

In the pathway that we are proposing for the formation of organosele-nides, we also postulate the formation of a selenium (II) ester as the first step of the reaction. Further reaction of this ester with olefins followed by solvolysis will produce an intermediate alkylselenenic acid. Addition of this acid to an olefinic double bond will produce the type of selenide found in this system. 

Interest in synthetic naphthenic acid has grown as the supply of product has fluctuated, Oxidation of naphthene-based hydrocarbons, free-radical addition of carboxylic acids to olefins, and addition of unsatnrated fatty acids to cycloparaflins have been studied but not commercialized. 

Strong differences in the reactivity of the aromatic C=C double bond compared to the reactivity of the C=C double bond of olefins are observed olefinic electrophilic additions are faster than aromatic electrophilic substitutions. For instance, the addition of molecular bromine to cyclohexene (in acetic acid) is about 1014 times faster than the formation of bromobenzene from benzene and bromine in acetic acid113,114. Nevertheless, the addition of halogens to olefins parallels the Wheland intermediate formation in the halogenation of aromatic substrates. 

Protonation and hydrolysis of the extended enol ether to release the enone may occur during work-up and the stable enone is the first compound that can be isolated. The 50% yield of this compound represents a much better yield in four steps fragmentation, olefin cyclization, addition of formic acid, and enol ether hydrolysis. 

Dondoni A, Marra A, Merino P (1994) Installation of the pyruvate unit in gly-cidic aldehydes via a Wittig olefination-Michael addition sequence utilizing a thiazole-armed carbonyl ylide. A new stereoselective route to 3-deoxy-2-ulosonic acids and the total synthesis of DAH, KDN, and 4-epi-KDN. J Am ChemSoc 116 3324... 

The alkylation acid penalty for ethylene is so large it makes close control of the feed deethanizer absolutely mandatory for economical overall operation. The ethane and lighter content of the C3-C4 cut should be maintained nil as measured by continuous chromatography. Even a trace amount of C2 s may represent several barrels of ethylene per day. In addition, if a slug of ethylene is accidentally charged to the alkylation reactor it can also have the effect of suddenly reducing the strength of the acid catalyst to the point that alkylation ceases, olefin absorption rapidly dilutes the acid, and chain polymerization of olefins ("acid runaways") can occur. 

Jang et al. reported a highly diastereoselective tandem radical reaction to prepare -polysubstituted homoallylic alcohols (Scheme 64) [175]. This new process relies on the initial addition of benzoyl radicals onto an olefin. The intermediate radicals such as 201 underwent a stereoselective vinylation (two elementary steps) to form the desired Bz-protected homoallylic alcohols in good yields. The stereochemical outcome of the reaction is strongly dependent on polar factors such as solvent polarity of Lewis acid additives. More sophisticated domino processes including cyclizations can be devised, as is the case for the formation of 203. 

Engman reported that the acetoxyselenenylation of alkenes could be better carried out with PhSeBr in acetic acid in the presence of acetic anhydride and KNO3 [40]. In the case of terminal olefins the addition proceeds with poor regio-control. However, when the chloroform solution of the two products was treated with catalytic amounts of boron trifluoride etherate, isomerization takes place and the anti-Markovnikov adduct was transformed into the Markovnikov product. The acetoxyselenenylation of alkenes can be cleanly effected also by oxidation of diphenyl diselenide with iodobenzene diacetate in acetonitrile [22]. 

A wide variety of dehydrating agents have been employed. In addition to those already mentioned are sulfuric acid, potassium bisulfate, formic acid, thionyl chloride, iodine, acetic anhydride, phosphorus oxychloride, and phosphorus pent-oxide. It should be noted that the free olefinic acids are sometimes decatboxylated under conditions similar to those described for certain of these dehydrations (cf. method 27). 

In the above reactions the aryl group adds to the a- rather than to the jB-catbon atom of the a,yS-olefinic acid. The reverse addition occurs in the conversion of acrylonitrile to cinnamonitrile (33%) (cf. method 20). 

Silver oxide, easily prepared from silver nitrate and sodium hydroxide, is probably the best reagent for the preparation of pure acids from aldehydes. An additional advantage is that it does not attack other easily oxidizable groups in the molecule. Typical examples are 3-thiophene-carboxylic acid (97%), palmitic acid (98%), and anthracene-9 carboxyIic acid (72%). Its use in the preparation ol olefinic acids from olefinic aldehydes is illustrated by the preparation of 2-methyI-2-pentenoic acid (60%). Organic peracids have also been used in the oxidation of aldehydes to carboxylic acids. ... 

The hydrolysis of thiol esters is achieved in either acidic or basic media. Alcoholic solutions of hydrogen chloride or potassium hydroxide are the most common reagents. Dithiols, hydroxy mercaptans/ and mercapto ethers, ketones, and acids have been prepared by this method. The corresponding thiol esters are obtained by the addition of thioacetic acid to oxides and olefinic acids or by the action of its potassium salt on halo ketones or sulfonic esters. ... 

Aqueous solutions of bisulfites react with olefins in the presence of oxygen or certain oxidizing agents. Addition of the bisulfite takes place by a free-radical mechanism contrary to Markownikoff s rule. The yields of sulfonates are usually low (12-62%). Styrene gives mainly 2-hydroxy-2-phenylethanesulfonic acid. Bisulfite has also been added to the double bonds in allyl and cinnamyl alcohols. /3-Sulfocarboxylic acids are prepared in this way from a,/3-olefinic acids. /3,/3-Disulfopropionic acid is made in 80% yield by the addition of two molecules of bisulfite to... 

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