Publisher Summary The aim of this chapter is to review some recent work on carbenes and carbenoid reactions in solution. The selection of material is made according to the personal interest and assessment of the value of the work. It should be evident that the study of carbene is a lively and fertile area of chemical experimentation and speculation. The body of accepted experimental data is small and fragmentary, and the scope for further investigation is vast. Little seems to be understood about the interaction of the divalent carbon atom with the substituents attached to it and the effect of this interaction on reactivity. Features that are commonly taken to characterize carbenoid reactions are: (1) the formation of cyclopropanes from olefins; (2) the insertion of a group CRR’ into a single bond; and (3) the formation of dimeric olefins from CRR’-groups. Structures are designated using the system of nomenclature in which carbenes are treated as derivatives of the parent species methylene (CH 2 ). Carbenes are formed and can be directly observed both in the gas phase and in solid solutions under appropriate circumstances. Methylene is highly energetic and reacts virtually at every collision. There appears to be a duality of mechanism in the base-induced decomposition of tosylhydrazones, products arising from both carbenes and carbonium ions. The structures of the products are an unreliable guide to their precursors, and the use of deuteriated tosylhydrazones or solvents is preferable for this purpose.

The Thermal Decomposition of α,α-Dihalodialkylmercury Compounds1

Structure and Mechanism in Carbene Chemistry

Publisher Summary All the elements of Group I1 (with the exception ofradium) are known to form alkyl derivatives. The compounds from magnesium and mercury are of very great interest and importance, the former because of their usefulness in synthesis, and the latter because of their physiological activity; as a consequence, so many of the compounds have been prepared and the literature on their properties is so extensive that a detailed account of their chemistry, even if confined to recent advances, is beyond the scope of a review article. Nevertheless, recent studies of the alkyl derivatives of all the Group I1 metals have revealed a pattern of structure and behavior that may make possible some rationalization of the properties and reactions of metal alkyls in general, and promise to lead to a greater insight into the nature of carbon-metal bonds. Good accounts of the older chemistry of the alkyl derivatives of the Group I1 metals have been given in monographs on organometallic Chemistry. The emphasis will be on the structural chemistry of the compounds. A detailed account of their reactions is not attempted, although the more important work on the influence of structure and solvation on reactivity is reviewed.

The Thermal Decomposition of α,α-Dihalodialkylmercury Compounds1

Citations

Structure and Mechanism in Carbene Chemistry

Alkyl Derivatives of the Group II Metals

Halomethyl-metal compounds : XLVII. Phenyl(1,1-dichloroethyl)mercury, a potential CH3CCl transfer agent

Halomethyl-metal compounds

CHAPTER 3 – Organometallic Methylene Transfer Agents

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