Reactions of acylpolysilanes with silyl Lewis acids

The reaction of acylpolysilanes with TMSOT and TMS(NTf₂) proceed via a series of 1,2 silyl and silyoxy shifts to afford the silanol products 5 and 6 respectively. A unified mechanistic pathway involving the formation of transient silenium ion complexes and silenes which rationalises these products is proposed. The structural assignment of the products is supported by X-ray structures for the phenyl 6a and trifluoromethylphenyl 6b substituted silanols.