Electrophilic Behavior of the "Nucleophilic" Pyramidane: Reactivity of Ge-Pyramidane towards Organolithium Reagents.

The particular reactivity of the recently discovered class of the main group element polyhedral clusters, pyramidanes, remains largely unexplored. In this communication, we report the reaction of the germapyramidane with tert-butyllithium leading to the rather unusual organogermanium compound [Li(thf)]⋅2, as the product of the formal insertion of a Ge-apex into the C-Li bond. This reactivity mode exemplifies unusual electrophilic behaviour of a pyramidane, which is a priori considered as a nucleophilic reagent.

Heavy Tetrel Clusters Based on the Bicyclobutane Framework: Bicyclo[1.1.0]butanes, [1.1.1]Propellanes, and Tricyclo[2.1.0.0 ]pentanes.

In this review, the current state of affairs in the novel field of the group 14 element clusters based on the bicyclo[1.1.0]butane framework, namely, bicyclo[1.

Pyramidanes: newcomers to the anti-van't Hoff-Le Bel family.

In this feature article, an overview of the chemistry of pyramidanes, as a novel class of main group element clusters, is given. A general introduction sets the scene, briefly presenting the non-classical pyramidal geometry of tetracoordinate carbon, as opposed to the classical tetrahedral configuration. Pyramidanes, as the simplest organic compounds possessing a pyramidal carbon atom, are then discussed from both computational and experimental viewpoints, to show the theoretical predictions on the stability and thus the feasibility of pyramidanes has finally culminated in the isolation of the first stable representatives of the pyramidane family featuring heavy main group elements at the apex of the square pyramid.

From a (Silatrigerma)cyclobutenylium Ion to a (Silatrigerma)cyclobutenyl Radical and Back.

(Silatrigerma)cyclobutenylium ion salt was readily prepared by the reaction of cyclotrigermene with an equimolar amount of [EtSi(benzene)][B(CF)] in benzene. The homoaromatic nature of was firmly established by its crystallographic analysis, which revealed a highly folded SiGe four-membered ring (40.4°) and a remarkably short transannular Ge-Ge distance of 2.