The reaction of chlorodimethylvinylsilane with tertbutyllithium was investigated in the presence of several conjugated dienes. In all cases except with 2,5-dimethylfuran, [2+4] cycloadducts of a silene intermediate are obtained in hydrocarbon solvents. The presence of THF in the reaction mixture suppresses the formation of cycloadducts in favor of 1,3-disilacyclobutanes. In the reaction of dimethylethoxyvinylsilane or dimethylmethoxyvinylsilane with tert-butyllithium the main product is the 1,1-dimethyl2-neopentyl-4-(dimethylalkoxysilyl)silacyclobutane. It is concluded that lithium chloride elimination to give silene intermediates occurs in hydrocarbon solvents. In the presence of strong Lewis bases or when the leaving group on silicon is an alkoxy group, the addition reaction giving a-lithiosilanes occurs and products arising from their coupling reactions are obtained.

Call number: LD2668 .T4 1961 E54

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A general method for the formation of acetals using chlorotrimethylsilane has been developed. Dioxolanes are formed from most carbonyl groups whereas methyl acetals are only formed from electron-poor carbonyl groups. The intermediacy of a silicon-bound carbonyl species is discussed. / The method has been extended to the formation of esters. In a solution of the alcohol to be esterified, methyl, ethyl, benzyl and 2-trimethylsilylethyl esters are readily formed in the presence of chlorotrimethylsilane. Using ('29)Si-N.M.R., a trimethylsilyl ester has been shown to be an intermediate in the reaction. / The Lewis acid catalyzed condensation of 1,3-bis-trimethylsiloxy-1-methoxy-1,3-butadiene with a variety of dielectrophiles, in a 1,2 relationship, has been investigated. The relative order of electrophilic reactivity towards this compound has been found to be; RR'C(Cl)SC(,6)H(,5) > ArCOCHO > ArCOCHO > RC(OCH(,3))(,2),RC(OCH(,3))SC(,6)H(,5) > RCHCl(,2). The dialkylation of 1,3-bis-trimethylsiloxy-1-methoxy-1,3-butadiene has been shown to lead to hydroxycyclopentenones with the same substitution pattern as the prostaglandins skeleton. Using ('29)Si-N.M.R., the mechanism of this reaction has been shown to proceed in two sequential steps; reaction of the (gamma)-position takes place first to give a titanium-bound intermediate, the thus formed intermediate then undergoes (alpha)-alkylation to give the cyclopentenone compound.

Thesis (Ph.D.) -- McMaster University, 1998. / Includes bibliographical references (leaves 209-217). Also available via World Wide Web.