C-O and C-C bond formation in the cyclisation of gem-(dialkoxymethyl)-1,6-dienes catalysed by tin(IV) triflimidate at room temperature

We described herein a Sn(NTf₂)₄-catalysed cyclisation of gem-(dialkoxymethyl)-1,6-dienes and derivatives where cyclohexane or tetrahydrofuran rings are formed following either a 6-enexo-endo-trig process or a 5-exo-trig process, respectively, depending on substitution patterns. The latter process features an unusual dealkylative ether cyclisation, triggered by the strong Lewis acid character of the tin(IV) triflimidate catalyst.