Flash Communication: Addition of Acid Anhydrides to Monomeric Stibine Oxides.

The polarized and unsaturated Sb-O bond of stibine oxides exhibits a combination of electrophilicity at the antimony atom and nucleophilicity at the oxygen atom. Here, we explore the consequent ability of Mes3SbO compounds to undergo 1,2-addition chemistry with carboxylic, sulfonic, and phosphinic acid anhydrides to afford stiboranes of the type Mes3SbX2. With the bulkier stibine oxide Dipp3SbO, reaction with triflic anhydride permits in situ preparation of Dipp3Sb-(OTf)2, which crystallized as the stibonium triflate salt. This reactivity also enables the disaggregation of the polymeric stibine oxide (Ph3SbO)n under mild conditions, providing an alternative synthetic route to Ph3SbX2 products.