Activation of allenes by gold complexes: a theoretical standpoint.

This review provides an insight into the activation of allenes by gold complexes toward nucleophilic attack. The various possible geometries of allene-gold species, from η(2)-allenes to η(1) allylic cations, are described. From the data collected in the literature, it is clear that all of these intermediates have been met during computational analysis of reaction mechanisms. While some retain the stereochemical information of the starting optically active allenes, others may lose it by planarization. To shed light on that matter, the factors governing axial-to-center chirality transfer are described. Some concepts are illustrated by selected examples of catalytic transformations, the mechanisms of which have been studied computationally.