Reversible Dissociation of a Dialumene

Dialumenes are neutral Al(I) compounds with Al=Al multiple bonds. We report the isolation of an amidophosphine‐supported dialumene. Our X‐ray crystallographic, spectroscopic, and computational DFT analyses reveal a long and extreme trans‐bent Al=Al bond with a low dissociation energy and bond order. In solution, the dialumene can dissociate into monomeric Al(I) species. Reactivity studies reveal two modes of reaction: as dialumene or as aluminyl monomers

Hydrofunctionalisation of an Aromatic Triphosphabenzene

The aromatic heterocycle 2,4,6-tri-tert-butyl-1,3,5-triphosphabenzene reacts with a series of silanes, germanes and stannanes, with weaker E-H bonds reacting in an increasingly facile manner. All react by 1,4-addition to give bicyclic products with diastereomeric ratios varying with the substrate. Density functional theory (DFT) calculations show that activation of the E-H bond occurs across the 1,4-C/P axis of the triphosphabenzene, with the small energetic differences with respect to the stereochemistry of the addition offering insight into the experimentally observed diastereomeric ratios

A Transient Vinylphosphinidene via a Phosphirene–Phosphinidene Rearrangement

A room-temperature-stable crystalline 2<i>H</i>-phosphirene (<b>1</b>) was prepared by treatment of an electrophilic diamidocarbene with <i>tert</i>-butylphosphaalkyne. Compound <b>1</b> is shown to react as a vinylphosphinidene generated via phosphirene–phosphinidene rearrangement. Thermolysis is shown to affect C–N bond scission while reactions with C₆Cl₄O₂ or (tht)­AuCl afford formal oxidation of the phosphindene center and the phosphinidene-insertion into an aromatic C–C bond of a mesityl group, respectively. The latter reaction is the first example of a phosphorus analog of the Büchner ring expansion reaction

Délibérations / Conseil municipal de Paris

05 avril 19381938/04/05 (N9)