Reactions d'insertion de fluorogermylenes sur diverses liaisons σ. Nouvelles syntheses de derives polymetalles du groupe IVB

Abstract

Difluorogermylene which exhibits a strong carbene activity gives many insertion reactions in σ bonds. In the same type of reactions, the lower reactivity of phenylfluorogermylene is generally similar to reactivity of the phenylchlorogermylene. The polymetallated derivatives of Group IVB metals formed by insertion reactions of these germylenes in σ bonds, like metalhalogen, metalhydrogen, metaloxygen, metalsulfur, metalnitrogen and metalmetal bonds, have low stability and thermally decompose via α-elimination processes to form germylenes and fluoro-organometallics. The polymetallated derivatives have been characterised by spectroscopy and chemical investigations: alkylation or arylation of their M(IVB)X bonds (X = halogen, oxygen etc.). The insertation reactions of difluoro-, phenylfluoro- and phenylchloro-germylenes into the intracyclic germaniumoxygen bond of diastereoisomeric oxaermacycloalkanes are generally stereospecific and can be interpreted by a concerted mecanism.