W-chlorosuccinimide

Synthetic procedures are available for the preparation of fluoro, chloro, bromo and iodo compounds from the corresponding lithio derivatives. Perchloryl fluoride (FC103), W-chlorosuccinimide, bromine and iodine are examples of reagents which can be used to introduce fluorine, chlorine, bromine and iodine, respectively. 

Apart from sodium hypochlorite, a number of alternative secondary oxidants for TEMPO-mediated alcohol oxidations can be employed. These include cerium (IV) ammonium nitrate (CAN),24 trichloroisocyanuric acid (TCCA),25 oxone ,26 MCPBA,2,3,7 PhI(OAc)2,27 W-chlorosuccinimide,28 sodium bromite,29 electrooxidation,8,21 H5IO626 and a polymer-attached diacetoxybromide (I) complex.30... 

SeC6H5 Hi Wittig HsCfiSe. H HjNCbz (3 equiv) Et3N (6 equiv) W-chlorosuccinimide (3 equiv) CH3OH 0 C Z- 1... 

Halogens, A/-bromo- and W-chlorosuccinimide, thionyl chloride, phosphorus oxychloride... 

For small-scale work the chlorination is also conveniently carried out by. W-chlorosuccinimide (Kenner, Todd and Weymouth, J. Chem. Soc. 1962, p. 3575). In this case no acid by-product is obtained. This modification is discussed in Chapter iv. 

Oxidation of Alcohols. AA(1,1-Dimethylethyl)benzenesul-fenamide is most commonly used as a catalyst for the oxidation of alcohols to aldehydes and ketones. The reaction requires the use of stoichiometric amounts of W-chlorosuccinimide (NCS) in order to convert the sulfenamide to the corresponding sulfinimidoyl chloride, which is the active oxidant in the reaction. In addition, it is necessary to perform the reaction in the presence of a base, most commonly potassium carbonate, in order to trap the HCl that is formed. The yield of the reaction is improved by the presence of a dehydrating agent, usually molecular sieves (MS). The preferred solvent for the reaction is dichloromethane. 

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