ALCOHOLS AND THIOLS

A major difference between alcohols and thiols concerns their oxidation We have seen earlier m this chapter that oxidation of alcohols gives compounds having carbonyl groups Analogous oxidation of thiols to compounds with C=S functions does not occur Only sulfur is oxidized not carbon and compounds containing sulfur m various oxida tion states are possible These include a series of acids classified as sulfemc sulfimc and sulfonic according to the number of oxygens attached to sulfur... 

Aliphatic Alcohols and Thiols. Ahphatic alcohols on reaction with chloroformates give carbonates and hydrogen chloride. Frequendy, the reaction proceeds at room temperature without a catalyst or hydrogen chloride acceptor. However, faster reactions and better yields are obtained in the presence of alkaU metals or their hydroxides, or tertiary amines. Reactions of chloroformates with thiols yield monothiolocarbonates (14). 

As mentioned in the introduction, l-heterobut-l-en-3-ynes, RXCH=CHC=CH (X = RN, O, S R = organic radical), are the nearest and most important diacetylene derivatives readily formed by nucleophilic addition of amines, alcohols, and thiols to diacetylene. In many heterocyclization reactions (especially those leading to fundamental heterocycles) l-heterobut-l-en-3-ynes behave as diacetylene synthetic equivalents, but unlike diacetylene, they are nonhazardous. Therefore, the syntheses of heterocycles therefrom are often more attractive in preparative aspect. 

A series of reactions was developed to transfer amines to ureido- and thioureido-derivatives for separation. The reaction of ureido-derivatives is widely used by the reaction with 1-phenylethyl isocyanate (PEIC) [8] or the naphthyl-analogue 1-(1-naphthyl)ethyl isocyanate (NEIC) [9]. Both reactions can be used not only for chiral amines but also for alcohols and thiols. 

SECTION 32 ALCOHOLS AND THIOLS FROM ACID DERIVATIVES... 

ALCOHOLS AND THIOLS FROM ETHERS, EPOXIDES AND THIOETHERS... 

Additional examples of ether cleavages may be found in Section 45A (Protection of Alcohols and Thiols). 

SECTION 45 ALCOHOLS AND THIOLS FROM MISCELLANEOUS COMPOUNDS... 

A preparation of 3-substituted thiete dioxides takes advantage of the commercial availability of the parent four-membered thietanes. The latter is oxidized to the sulfone, which in turn is photochemically mono- or di-chlorinated in the 3-position. The 3-chlorothietane dioxide (239a) can be easily transformed into the thiete dioxide, whereas the 3,3-dichloro homolog is transformed into the 3-chloro-2H-thiete 1,1-dioxide (240b) (equation 91). 240b reacts with carbanions, amines, alcohols and thiols to give the corresponding 3-substituted thiete dioxides. ... 

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