Selective functionalization of a bis-silylene

Functionalization of N-heterocyclic carbenes (NHCs) has an important influence on their stability, Lewis donor, and acceptor properties. In this study, we report on the selective functionalization of a four-membered N-heterocyclic bis-silylene (2,6-Ar2C6H3NSi:)(2) (1) (Ar = 2,4,6-iPr(3)C(6)H(2)) with mono-oxygen sources N2O and Me3NO. Treatment of 1 with N2O results in the selective formation of mono-silylene (2,6-Ar2C6H3NSi(OH)(2))(2,6-Ar2C6H3NSi:) (2) as a major product, along with a small amount of further oxidized product (2,6-Ar2C6H3NSi(OH)(2))(2) (3). Compound 2 is the first four-membered mono-silylene with a di-coordinate silicon atom.