A silylene-stabilized distannavinylidene with a highly labile substituent

Vinylidene and its heavier analogues are fundamentally important in synthetic chemistry, but their stabilization and structural characterization remains extremely challenging. Herein we describe that the reduction of an NHSi-stabilized stannyl-stannylene (2) with one molar equivalent of [( Mes Nacnac)Mg] 2 affords an NHSi-stabilized distannavinylidene (3) . Single-crystal X-ray crystallography and density functional theory (DFT) calculations show that compound 3 features a pronounced Sn=Sn double bond and one lone pair of electrons at the two-coordinate Sn atom. Most strikingly, 3 undergoes an interconversion with distannyne (4) upon the addition and removal of one molar equivalent of N-heterocyclic carbene. Compound 3 readily reacts with Ph 2 C=C=O, AdC≡P and (AlCp*) 4 to give the structurally interesting stannacycles (5, 6) and an aluminyl distannyne (7) , demonstrating its unique reactivity derived from the high substituent lability.