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Thiols are efficiently converted to alkyl halides in high to excellent yields when treated with triphenylphosphin/N-halosuccinimide (halogen: Br,Cl, and I) in dichloromethane at room temperature.Although the conversion of alcohols to alkyl halides with tertiary phosphines and electrophilic halogens has widely been studied 1-9 the reports on the formation of alkyl halides from thiols are scarce. Some of these reports are considered as follow; organic halides and tertiary phosphinsulfides are coproduced by heading a thiol with a tertiary phosphine/X 2 10a (X = Cl, Br) in solvent. This reaction with iodine has been reported to occur in the presence of pyridine or tertiary butyl amine as a base. 10b The reaction of thiols with triphenyl-and trialkyl-phosphines and poly halogenomethanes especially carbon tetrachloride, to give alkyl chlorides has also been reported. 4 In addition, thiols were converted to alkyl chlorides by reaction with carbon tetrachloride and cross-linked polystyrenes containing phosphine residues, 5a Ph 3 P/chlorocarbonylsulfenyl chloride, 5b or Ph 3 P/sulfuryl chloride. 5c In spite of oxidation of thiols to disulfides by N-bromosuccinimide, 11 and in relation with our pervious works on the use of triphenylphosphine/(SCN) 2 , 12,13 we introduce a very simple, mild and efficient method for the conversion of thiols to alky halies (X = Cl, Br, and I) using a combination of triphenylphosphine and N-halosuccinimide (PPh 3 / NXS, X:Cl, Br, and I) in dichloromethane at room temperature (Scheme 1). Scheme 1In order to optimize the reaction conditions, we first examined the effect of different ratios of triphenylphosphine /N-bromosuccin-imide (PPh 3 /NBS) as brominating agent on the conversion of 1-buthanethiol to 1-bromobutane. As shown in Table 1, entry 5, when the stoichiometry of PPh 3 is slightly more than NBS, the oxidation of thiol to disulfide is minimized and alkyl halide is obtained in its highest yield. Table 1 a) GC analysis using n-octane as internal standard.

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An efficient and rapid method is described for the reductive Claisen rearrangement of different propargyloxyanthraquinones to anthra[1,2-b]furan-6,11-diones for first time using iron powder in a mixture of two ionic liquids, namely 1-methylimidazolium tetrafluoroborate [Hmim]BF4 and 1-benzyl-3-methylimidazolium chloride [Bzmim]Cl. The present method is able to execute single or double Claisen rearrangements of 1,4- or 1,5-bispropargyloxyanthraquinones selectively, so that the desired anthra(mono)furandiones or anthra(bis)furandiones are produced, respectively, as the major product.