16478-18-5Relevant articles and documents
THE PREPARATION AND SOME REACTIONS OF 2,3,5,6-TETRACHLOROPHENYLMAGNESIUM CHLORIDE
Rahman, M. T.
, p. 25 - 30 (1982)
The reaction of pentachlorobenzene with metallic magnesium in THF at 10-15 deg C gives after hydrolysis 1,2,4,5-tetrachlorobenzene (76percent) and pentachlorobenzene (8percent); after trimethylsilylation, 1,2,4,5-tetrachloro-3-(trimethylsilyl)benzene (74percent), pentachloro(trimethylsilyl)benzene (8percent) and 1,2,4,5-tetrachlorobenzene (6percent); after iodination, 1,2,4,5-tetrachloroiodobenzene (44percent), pentachloroiodobenzene (12percent) and 1,2,4,5-tetrachlorobenzene (9percent); and finally after carbonation, 2,3,5,6-tetrachlorobenzoic acid (58percent).These products indicate that in the Grignard reaction a mixture of largely 2,3,5,6-tetrachlorophenylmagnesium chloride and some pentachlorophenylmagnesium chloride is formed.The formation of pentachlorophenylmagnesium chloride is explained on the basis of metal-hydrogen exchange reaction between 2,3,5,6-tetrachlorophenylmagnesium chloride and the unreacted pentachlorobenzene.
In situ generation and trapping of aryllithium and arylpotassium species by halogen, sulfur, and carbon electrophiles
Popov, Ilya,Do, Hien-Quang,Daugulis, Olafs
supporting information; experimental part, p. 8309 - 8313 (2010/01/16)
(Chemical Equation Presented) A general method has been developed for in situ trapping of arylmetal intermediates by halogen, sulfur, ketone, and aldehyde electrophiles affording the functionalization of the most acidic position in arene. Pentafluorobenzene, benzothiazole, and benzoxazole can be functionalized by using K3PO4 base. For less acidic arenes, tBuOLi base is required. Arenes with DMSO pKa values of 35 or less are reactive. 2009 American Chemical Society.
Nucleophilic Displacement in Polyhalogenoaromatic Compounds. Part 11. Kinetics of Protiodeiodination of Iodoarenes in Dimethyl Sulphoxide-Methanol
Bolton, Roger,Moore, Clive,Sandall, John P.B.
, p. 1593 - 1598 (2007/10/02)
The rates of methoxide-ion induced protiodeiodination of a number of polychloroiodobenzenes and their derivatives have been measured in dimethyl sulphoxide-methanol (9:1 v/v; 323.2 K).The true reagent under these conditions appears to be the dimethyl sulphoxide anion, and the rates of reaction in some cases appear to approach that expected of a diffusion controlled process.This corresponds to a major decrease in the efficacy of further activating substituents in the aromatic system, altough deactivating groups such as p-OMe still show large effects.Chlorine promotes protiodeiodination in the order of efficiency o-Cl > m-Cl > p-Cl; the trifluoromethyl group activates displacement in the order o-CF3 > p-CF3 > m-CF3, although with much less difference between isomeric sites. o-Nitro-groups promote protiodeiodination whereas the p-nitro-group encourages methoxydeiodination.No evidence of methoxydeiodination was found in attack of the polychloroiodobenzenes, although the rates of methoxydechlorination of the corresponding polychlorobenzenes suggest that in some cases this might occur.Evidence rejecting the possible SRN1 mechanism and supporting nucleophilic attack by a carbanionic species upon iodine is presented.
