Sulfonic acids, addition alkenes

Acid-Gatalyzed Synthesis. The acid-catalysed reaction of alkenes with hydrogen sulfide to prepare thiols can be accompHshed using a strong acid (sulfuric or phosphoric acid) catalyst. Thiols can also be prepared continuously over a variety of soHd acid catalysts, such as seoHtes, sulfonic acid-containing resin catalysts, or aluminas (22). The continuous process is utilised commercially to manufacture the more important thiols (23,24). The acid-catalysed reaction is commonly classed as a Markownikoff addition. Examples of two important industrial processes are 2-methyl-2-propanethiol and 2-propanethiol, given in equations 1 and 2, respectively. 

Two types of sulfonate esters can be formed in the production of AOS. Neutral esters are formed by the addition of alkenesulfonic acid to alkene (Fig. 29). Acid esters are formed by the dimerization of two alkene mono- or disulfonic acids (Fig. 30). These would normally be expected to hydrolyze in the saponification stage of the process. 

Organoboranes react with a mixture of aqueous NH3 and NaOCl to produce primary amines. It is likely that the actual reagent is chloramine NH2CI. Chloramine itself,hydroxylamine-O-sulfonic acid in diglyme, and trimethyl-silyl azide " also give the reaction. Since the boranes can be prepared by the hydroboration of alkenes (15-16), this is an indirect method for the addition of NH3 to a double bond with anti-Markovnikov orientation. Secondary amines can be prepared by the treatment of alkyl- or aryldichloroboranes or dialkylchlorobor-anes with alkyl or aryl azides. 

A variety of functional groups resist reduction arene rings, N02, COOMe, CONH2, sulfones, nitrile, and ArHal. Nitriles can bind to the metal, and the N lone pair is not effectively masked by acid addition so lower rates can be encountered if this group is present. Alkynes, alkenes, and imines are the best-studied substrates for which reduction is efficient. 

Figure 3.53 shows an addition of a carboxybc acid to isobutene, which takes place via the tert-butyl cation. This reaction is a method for forming ferf-butyl esters. Because the acid shown in Figure 3.53 is a /i-hydroxycarboxylic acid whose alcohol group adds to an additional isobutene molecule, this also shows an addition of a primary alcohol to isobutene, which takes place via the ferf-butyl cation. Because neither an ordinary carboxylic acid nor, of course, an alcohol is sufficiently acidic to protonate the alkene to give a carbenium ion, catalytic amounts of a mineral or sulfonic acid are also required here. 

Reaction with concentrated sulfuric acid. Alkenes react with cold concentrated sulfuric acid by addition. Alkyl sulfonic acids form as products and are soluble in H2S04. 

Cyanamide undergoes smooth addition to alkenes at 25 °C in the presence of A -phenylselenoph-thalimide (7V-PSP) and sulfonic acid as the catalyst, to produce /J-phenylseleno cyanamides in good yield, despite the long reaction times needed, anti- and. mi-Diastereomers 2, obtained from ( )- and (Z)-2-decene, respectively, are clearly distinguished on the basis of their H- and 13C-NMR spectra66. 

SILANES addition of silanes to alkene 15-19 SULFONIC ACIDS ... 

In a study by Wicha directed to the synthesis of prostaglandins from the Corey lactone, the use of BFs-EtaO to catalyze the addition of the lithium sulfone anion (470) to aldehydes was demonstrated (equation 109). The use of Lewis acid catalysis results in significantly improved yields for the addition component of the Julia coupling. In this example, the addition of either the lithium or the magnesium sulfone anion proceeded in low yield. With the addition of BF3-Et20, the p-hydroxy sulfone can either be isolated, or directly converted to an alkene in one pot. This sequence was originally developed to deal with the specific problem of a-hydroxy aldehydes, and the difficulty of sulfone anion addition to these adducts. Other problems with addition of the sulfone adduct may be amenable to this solution as well. 

Both these reagents will react with alkyl halides in aqueous media to give the corresponding sulfonic acids (21). This procedure has been used extensively for the preparation of aliphatic sulfonic acids in good yields (see Chapter 7, p. 100). Sodium hydrogen sulfite will also form sulfonic acids by addition to alkenes in the presence of peroxide catalysts (anti-Markownikoff reaction) (Scheme 19). 

One of the many important differences between phosphorus and nitrogen chemistry is the relative strengths of their bonds to hydrogen. The relatively weak P—H bond means that this functionality can be added across a wide variety of unsaturated molecules (alkenes, alkynes, carbonyls) and hence this represents an excellent method for preparing tertiary phosphines. The addition of P 11 compounds to C=0 and C=N has been described in detail by Gilheany and Mitchell.2 The reaction can be catalyzed by base (potassium hydroxide, butyllithium), acid (HC1, carboxylic acids, sulfonic acids, boron trifluoride), free radical (uv, organic peroxides, AIBN) or metal (simple metal salts, late transition-metal complexes). In some circumstances no catalyst is required at all for P 11 additions to proceed.60... 

The addition takes place according to Markownikoff s rule. The addition of carbo lic acida to the double bonds of isobutylene and trimethyl-ethylene gives tertiary esters. A true equilibrium independent of sulfuric acid concentrations is established in the exothermic reaction. The addition does not go well with ethylene, but goes well with many of the higher alkenes, particularly with some of the terpenes. To avoid the polymerizing effects of sulfuric acid, various other catalysts, such as sulfonic acids, triethylamine, hydrofluoric acid, boron trifluoride, and cuprous chloride have been used. The addition may take place at room temperature or higher and is aided by pressure. The vapors of the acid and hydrocarbon may be passed over catalysts, such as activated carbon, heteropoly acids, or metal phosphates. ... 

The present volume is a revised and enlarged third edition of the book formerly titled Tables for Identification of Organic Compounds, Four new classes of compounds, i.e., sulfonyl chlorides, sulfonamides, thiols and thioethers were added, bringing the number of classes included in the book to twenty-six. The tables of alkanes, alkenes, alkynes, aromatic hydrocarbons, phenols, nitriles and sulfonic acids were all thoroughly revised and considerably enlarged. In all, the addition of 2400 compounds to the third edition, raised the total number of parent compounds in the book to over 8150. 

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