Primary alcohols sulfides

Nickel peroxide is a solid, insoluble oxidant prepared by reaction of nickel (II) salts with hypochlorite or ozone in aqueous alkaline solution. This reagent when used in nonpolar medium is similar to, but more reactive than, activated manganese dioxide in selectively oxidizing allylic or acetylenic alcohols. It also reacts rapidly with amines, phenols, hydrazones and sulfides so that selective oxidation of allylic alcohols in the presence of these functionalities may not be possible. In basic media the oxidizing power of nickel peroxide is increased and saturated primary alcohols can be oxidized directly to carboxylic acids. In the presence of ammonia at —20°, primary allylic alcohols give amides while at elevated temperatures nitriles are formed. At elevated temperatures efficient cleavage of a-glycols, a-ketols... 

Both the second and third processes in Scheme 13 can also be used for the functionalization of a-silylated alkyl phenyl sulfides [74] when oxidizing the latter in the presence of primary alcohols. First, the cleavage of the C—Si bond (equivalent to deprotonation) and then that of the S—C bond occurs to give... 

Scheme 8 summarizes the introduction of the missing carbon atoms and the diastereoselective epoxidation of the C /C double bond using a Sharpless asymmetric epoxidation (SAE) of the allylic alcohol 64. The primary alcohol 62 was converted into the aldehyde 63 which served as the starting material for a Horner-Wadsworth-Emmons (HWE) reaction to afford an E-configured tri-substituted double bond. The next steps introduced the sulfone moiety via a Mukaiyama redox condensation and a subsequent sulfide to sulfone oxidation. The sequence toward the allylic alcohol 64 was com-... 

Interestingly, it is possible to employ diisopropyl sulfide in the place of dimethyl sulfide in Corey-Kim oxidations, in which case primary alcohols can be oxidized in the presence of secondary ones or vice versa, depending on reaction temperature.250... 

Interestingly, when a Corey-Kim oxidation (Me2S/NCS) is performed with diisopropyl sulfide, instead of dimethyl sulfide, primary alcohols are selectively oxidized at 0°C, while lowering the temperature to —78°C causes the selective oxidation of secondary alcohols.34... 

A classical Corey-Kim oxidation sometimes shows a certain preference for the oxidation of secondary alcohols.2 Additionally, a Corey-Kim oxidation, in which diisopropyl sulfide is employed in the place of dimethyl sulfide, presents a preference for the oxidation of primary alcohols at 0°C and secondary alcohols at -78°C.50... 

A primary alcohol and amines can be used as an aldehyde precursor, because it can be oxidized by transfer hydrogenation. For example, the reaction of benzyl alcohol with excess olefin afforded the corresponding ketone in good yield in the presence of Rh complex and 2-amino-4-picoline [18]. Similarly, primary amines, which were transformed into imines by dehydrogenation, were also employed as a substrate instead of aldehydes [19]. Although various terminal olefins, alkynes [20], and even dienes [21] have been commonly used as a reaction partner in hydroiminoacylation reactions, internal olefins were ineffective. Recently, methyl sulfide-substituted aldehydes were successfully applied to the intermolecu-lar hydroacylation reaction [22], Also in the intramolecular hydroacylation, extension of substrates such as cyclopropane-substituted 4-enal [23], 4-alkynal [24], and 4,6-dienal [25] has been developed (Table 1). 

Oxidation of primary and secondary alcohols. In contrast to dimethyl sulfide-NCS (4, 88-90), which oxidizes both primary and secondary alcohols, diisopropyl sulfide-NCS can effect selective oxidation of these substrates. At 0° it oxidizes only primary alcohols to aldehydes, but at —78° it oxidizes only secondary alcohols to ketones. However, allylic or benzylic alcohols are oxidized at either temperature. 

The use of A(-chlorosuccinimide/diisopropyl sulfide for the selective oxidation of primary/secondary diols was outlined earlier in Section 2.9.2.1, where it was used for the selective oxidation of the primary alcohol. Remarkably, by carrying out the reaction at -78 C (as compared to O C in the previous case) this reagent system becomes selective for secondary alcohols in the presence of primary alcohols (see Scheme 2 Section 2.9.2.1). 

An interesting example of this type of chemoselective oxidation has been reported with the reagent mixture derived irom (Uisopropyl sulfide and )V-chlorosuccinimide. This reagent will oxidize selectively a primary alcohol to an aldehyde at 0 C. Surprisingly, this same reagent at -78 C will oxidize selectively a secondary alcohol to the corresponding ketone (Scheme 2). Allylic and benzylic alcohols are oxidized at both temperatures. 

Thermal decomposition of methyl xanthates is similar to the pyrolysis of acetates for the formation of the double bond. Olefins are obtained from primary, secondary, and tertiary alcohols without extensive isomerization or structural rearrangement. The other products of the pyrolysis of the methyl xanthates are methyl mercaptan and carbon oxy-sulfide. The xanthates prepared from primary alcohols are more difficult to decompose than those prepared from secondary and tertiary alcohols. Over-all yields of 22-51% have been obtained for a number of tertiary alkyl derivatives of ethylene. Originally the xanthates were made by successive treatment of the alcohol with sodium or potassium, carbon disulfide, and methyl iodide. In a modification of this procedure sodium... 

Thiols have also been prepared from alcohols. One method involves treatment with H2S and a catalyst, such as Al203, but this is limited to primary alcohols. Another method involves treatment with Lawesson s reagent (see 16-10). When epoxides are substrates, the products are (3-hydroxy thiols. Tertiary nitro compounds give thiols (RNO2 —> RSH) when treated with sulfur and sodium sulfide, followed by amalgamated aluminum. ... 

The main applications of oxidation with chromium trioxide are transformations of primary alcohols into aldehydes [184, 537, 538, 543, 570, 571, 572, 573] or, rarely, into carboxylic acids [184, 574], and of secondary alcohols into ketones [406, 536, 542, 543, 575, 576, 577, 578, 579, 580, 581, 582, 583, 584]. Jones reagent is especially successful for such oxidations. It is prepared by diluting with water a solution of 267 g of chromium trioxide in a mixture of 230 mL of concentrated sulfuric acid and 400 mL of water to 1 L to form an 8 N CrOj solution [565, 572, 579, 581, 585, 556]. Other oxidations with chromic oxide include the cleavage of carbon-carbon bonds to give carbonyl compounds or carboxylic acids [482, 566, 567, 569, 580, 587, 555], the conversion of sulfides into sulfoxides [541] and sulfones [559], and the transformation of alkyl silyl ethers into ketones or carboxylic acids [590]. 

Sodium hypochlorite is used for the epoxidation of double bonds [659, 691] for the oxidation of primary alcohols to aldehydes [692], of secondary alcohols to ketones [693], and of primary amines to carbonyl compounds [692] for the conversion of benzylic halides into acids or ketones [690] for the oxidation of aromatic rings to quinones [694] and of sulfides to sulfones [695] and, especially, for the degradation of methyl ketones to carboxylic acids with one less carbon atom [655, 696, 697, 695, 699] and of a-amino acids to aldehydes with one less carbon [700]. Sodium hypochlorite is also used for the reoxidation of low-valence ruthenium compounds to ruthenium tetroxide in oxidations by ruthenium trichloride [701]. 

Bromine dehydrogenates alcohols to carbonyl compounds [682, 726, 729, 734] (secondary alcohols in preference to primary alcohols [682]) and hydrazo compounds to azo compounds [733] and oxidizes sulfides to sulf-... 

Sodium bromite, NaBr02 H20, a crystalline compound, oxidizes secondary alcohols to ketones [739] and sulfides to sulfoxides [739]. Primary alcohols are transformed into esters [739]. 

The spectrum of applications of potassium permanganate is very broad. This reagent is used for dehydrogenative coupling [570], hydrox-ylates tertiary carbons to form hydroxy compounds [550,831], hydroxylates double bonds to form vicinal diols [707, 296, 555, 577], oxidizes alkenes to a-diketones [560, 567], cleaves double bonds to form carbonyl compounds [840, 842, 552] or carboxylic acids [765, 841, 843, 845, 852, 869, 872, 873, 874], and converts acetylenes into dicarbonyl compounds [848, 856, 864] or carboxylic acids [843, 864], Aromatic rings are degraded to carboxylic acids [575, 576], and side chains in aromatic compounds are oxidized to ketones [566, 577] or carboxylic acids [503, 878, 879, 880, 881, 882, 555]. Primary alcohols [884] and aldehydes [749, 868, 555] are converted into carboxylic acids, secondary alcohols into ketones [749, 839, 844, 863, 865, 886, 887], ketones into keto acids [555, 559, 590] or acids [559, 597], ethers into esters [555], and amines into amides [854, 555] or imines [557], Aromatic amines are oxidized to nitro compounds [755, 559, 592], aliphatic nitro compounds to ketones [562, 567], sulfides to sulfones [846], selenides to selenones [525], and iodo compounds to iodoso compounds [595]. 

Cupric permanganate, Cu(Mn04)2 8H20, is commercially available and oxidizes primary alcohols and aldehydes to acids, secondary alcohols to ketones, and sulfides to sulfones in very high yields [894]. 

A single enzyme is sometimes capable of many various oxidations. In the presence of NADH (reduced nicotinamide adenine dinucleotide), cyclohexanone oxygenase from Acinetobacter NCIB9871 converts aldehydes into acids, formates of alcohols, and alcohols ketones into esters (Baeyer-Villiger reaction), phenylboronic acids into phenols sulfides into optically active sulfoxides and selenides into selenoxides [1034], Horse liver alcohol dehydrogenase oxidizes primary alcohols to acids (esters) [1035] and secondary alcohols to ketones [1036]. Horseradish peroxidase accomplishes the dehydrogenative coupling [1037] and oxidation of phenols to quinones [1038]. Mushroom polyphenol oxidase hydroxylates phenols and oxidizes them to quinones [1039]. 

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