Various alkoxy(N-tert-butylamino)(methyl)sulfonium triflates are prepared by selective O-alkylation of N-tert-butylmethanesulfinamide (4c) with primary alkyl trifluoromethane sulfonates (triflates). Successive treatment of thus formed alkoxyaminosulfonium salts with DBU smoothly affords the corresponding aldehydes in good yields. The sequential combination of the two reactions provides a new method for oxidation of primacy alkyl triflates to aldehydes, and the present study suggests the existence of alkoxysulfilimines as intermediates of the previously-reported direct oxidation of alcohols by using N-tert-butylphenylsulfinimidoyl chloride (1a) and DBU.