N-Chlorosuccinimide-Dimethyl sulfide

Selective conversiou of allylic and benzylic alcohols into halides It was noted above that allylic or benzylic alcohols are not oxidized by the N-chlorosuccinimide-dimethyl sulfide reagent but instead are converted into chlorides. Corey et al. now report that this procedure can be used to form allylic and benzylic chlorides in high yield if the sulfoxonium intermediate corresponding to (3, above) is allowed to decompose in methylene chloride without addition of a tertiary amine. For example, the allylic or benzylic alcohol is treated with the complex of N-chlorosuccinimide-dimethyl sulfide as above in methylene chloride and then allowed to stand for 4 hr. at - 25°. In the case of benzhydroi [(CfcH5)2CHOH], benzhydryl chloride can be obtained in > 95% yield. 

The reagent was used by Corey and Kim3 in an improved synthesis of prostaglandins. Thus oxidation of the hydroxy acid (5) to the keto acid (6) was effected in > 90% yield with use of N-chlorosuccinimide-dimethyl sulfide. The oxidation had been carried out previously with Jones reagent at —20° in about 70% yield. The carboxyl function... 

Chlorination of Aromatic Compounds. NCS has also been used for the chlorination of pyrroles and indoles however, the reaction is less straightforward than when NBS and N-Iodosuccinimide are used. In the chlorination of 1-methylpyrrole, it has been demonstrated that basic conditions (NaHCOs, CHCI3) lead to the formation of 1-methyl-2-succinimidylpyrrole (eq 11). In the presence of catalytic amounts of perchloric acid, thiophenes and other electron-rich aromatic compounds have been chlorinated with NCS. (N-Chlorosuccinimide-Dimethyl Sulfide is used for the selective -substitution of phenols.)... 

N-Chlorosuccinimide dimethyl sulfide triethylamine Corey oxidation Ketones from sec. alcohols... 

N-Chlorosuccinimide/dimethyl sulfide 3-Chloren-2-amines from enamines... 

Olefinic aldehydes have been synthesized by a variety of methods including oxidation of the corresponding primary alcohols with the chromium trioxide-pyridine complex 195—197) or N-chlorosuccinimide-dimethyl sulfide complex 198), heating a primary alken-l-yl mesylate with dimethylsulfoxide 199), or by alkylation of the lithium salt of 5,6-dihydro-2,4,4,6-tetramethyl-l,3-(4H)-oxazine with an alkynyl iodide followed by sodium borohydride reduction and acid hydrolysis (200). 

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