Date of Award
Doctor of Philosophy
Glen A. Russell
A new free radical chain process of alkyl radical additions to olefins has been discovered. The alkyl radical addition is initiated by the reaction of alkylmercury halides with silyl hydrides such as triethylsilane or phenylsilane. The process occurs at room temperature and gives satisfactory results only with dimethyl sulfoxide as solvent. This procedure produces regioselectively the reductive alkylation products in good yield for a wide variety of substituted olefins. The mechanism of this new process has been established through kinetic studies and product analysis. Experimental results have suggested that the reaction is a free radical chain process with the alkylmercury hydride as an intermediate. The alkylmercury hydride is formed slowly by the reaction of alkylmercury halide with a silyl hydride compound in dimethyl sulfoxide. The reaction of the silyl halide, which is formed from the atom exchange, with dimethyl sulfoxide is the driving force for the alkylmercury hydride formation. The alkylmercury hydride acts as the chain carrier as well as initiator for the reaction by providing alkyl radicals from decomposition;By using this new reaction procedure, the relative reactivities of a wide variety of substituted olefins have been measured by competition studies. The relative reactivity study suggests that the free radical alkylation of olefins is nucleophilic in character with an early transition state in a kinetically controlled process;A mechanistic study has also been carried out for the demercuration of 3,3-diacetylpropylmercuric chloride. 3,3-Diacetylpropylmercuric chloride showed unusual reactivity towards base to form 1,1-diacetylcyclopropane. The cyclization reaction is completely inhibited by the presence of diphenyl disulfide. Evidence is presented that the cyclization reaction proceeds by a nucleophilic substitution mechanism. On the other hand, the reaction of 3,3-diacetylpropylmercuric chloride with diphenyl disulfide under irradiation is proven to be a free radical chain process.
Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/
Bing Zhi Shi
Shi, Bing Zhi, "Reductive radical alkylations of substituted olefins by alkylmercury halides " (1993). Retrospective Theses and Dissertations. 10271.