A new sulfonium-salt-based iodine(I) reagent system for the vicinal functionalisation of glycals and enol ethers has been developed. The unprecedented iodine(I) complex, Me3SI(OAc)2, generated in situ from Me3SI and PhI(OAc)2, effectively promoted the one-pot iodocarboxylation using carboxylic acids, and iodoazidation using NaN3 or TMSN3 (trimethylsilyl azide). The scope and generality of the new reagent
Dihydropyran and glycals are readily converted to the corresponding trans-2-deoxy-2-haloazide derivatives in excellent yields within a few minutes using NIS/NBS-TMSN3 at rt in the absence of any catalyst. The use of stoichiometric amounts of the reagents under mild experimental conditions together with the simplicity of the reaction protocol is the notable feature of this transformation.