Reactions of strained organosilicon heterocycles with nonacarbonyldi-iron(0). Part I. Reactivity and mechanism

Abstract

The formation of 2,2,2,2-tetracarbonyl-1-sila-2-ferracyclopentanes by the reaction of silacyclobutanes with nonacarbonyldi-iron is described, and the nature of the process discussed. Completely regioselective reactions are found with Me₂[graphic omitted](Me)H[Si–CH₂ and not Si–C(Me)H cleavage] and with two silabenzocyclobutenes R₂[graphic omitted]H₂(R = Me or Ph)[C(arly)–Si and not C(alkyl)–Si cleavage]. With mixtures of the two isomers of XMe[graphic omitted]H₂(X = Buⁿ, isomer ratio 4:1: X = MeO, isomer ratio 7:3) the reaction is stereospecific, there being no significant change in isomer ratio between the reactant and product. It is concluded that this facile [Fe(CO)₄] insertion is probably an electrophilic C–Si cleavage reaction and that the process, using the term broadly, is concerted.