Reactions of methylene

Abstract

The research reported in this thesis concerns some reactions of the simplest organic entity - methylene.Reactivity of this species, indicative of its radical character was the reason why, though its presence in many chemical reactions was postulated in the last decade of the 19th century, the confirmation of its existence came much later, in the thirties of the present one, when the new techniques of investigation of unstable compounds such as the Paneth -mirror technique, were developed.From then till the 1950's the methylene reactions were the domain of organic chemists, who studied them mainly for their preparative applications.Invention of new analytical methods, such as mass spectrometry and gas chromatography, has enabled us to investigate these reactions quantitatively, with the prospect of elucidating the structure of methylene.The results of this work on reactions of methylene with 1,3 butadiene, butene -1, pentene -1 and tetrafluoroethylene are included in the first part of this thesis which attempts to be a survey of the methylene reactions, and can thus be regarded as the joint introduction and discussion.As the biradical nature of methylene, which would correspond to its triplet state, is still a matter of controversy and as, in many reactions methylene shows both radical and non -radical behaviour, no special division will be made between its monoradical reactions and those peculiar to biradicals, all reactions being classified into: -a) Insertionb) Abstraction and Displacement,and e) Addition reactions.The conclusions about the structure of methylene supported by studies of its reactions will be discussed in the paragraph "Structure of Methylene ".Unimolecular reactions of the cyclopropane derivatives, formed by the addition of methylene to a double bond of defins are the subject of the last paragraph in this survey.