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. Synthetic strategies towards pyramidanes, as well as their peculiar structural features, non-classical bonding situations, and specific reactivity, are presented and discussed in this review.

Automated summary

In this feature article, the chemistry of pyramidanes as a novel class of main group element clusters is discussed. The non-classical pyramidal geometry of tetracoordinate carbon is introduced, and the feasibility of pyramidanes is explored from computational and experimental perspectives. The isolation of stable pyramidane compounds featuring heavy main group elements at the apex of the square pyramid is presented, along with the synthetic strategies, peculiar structural features, non-classical bonding situations, and specific reactivity of pyramidanes.