Iodonium collidine triflate

For safety reasons it is probably advisable to substitute their iodonium(collidine)2 perchlorate, which is a potential explosive, with the corresponding triflate, which is made in the same manner as the perchlorate)]. 

Scheme 5.1 Mechanism of thioglycoside activation (a) by thiophiles X1 such as /V-bromosuccinimicle (NBS), 11,12 methyl triflate,13 dimethyl(methylthio)sulfonium triflate (DMTST),14 phenylselenyl triflate (PhSeOTf),17,18 iV-iodosuccinimide/triflic acid (MS/TfOH),19 20 and iodonium di-sym-collidine perchlorate (IDCP)21 (b) by tris(4-bromophenyl)ammoniumyl hexachloroantimonate (TBPA,+)25 and (c) via anomeric sulfoxides.26 The stereochemical outcome of these glycosylations follows the same general trends as with many other glycosyl donor/promoter combinations (m-CPBA = mcta-chloroperbenzoic acid).

Scheme 5.7 (a) Mechanism of the w-pentenyl glycoside-based glycosylation method. Electrophiles commonly employed include iodonium di-sym-collidine perchlorate (IDCP) and A-iodosuccinimide/triethylsilyl triflate (NIS/Et3SiOTf) (b) Mechanism for the activation of NIS by EtsSiOTf.55... 

Alternatively, Mootoo and coworkers [82,83] have developed a two-step iodoether-ification/Ag-catalyzed cychzation method for the synthesis of spiroacetals from homoallyhc alcohols 150 (Scheme 37). Treatment of the diol with iodonium dicollidine perchlorate (IDCP), followed by exposure to silver triflate in the presence of collidine affords the spiroacetals 154 in moderate to good yield as diastereomeric mixtures. This method was most recently applied in their synthesis of a simplified monensin analogue, polyether spiroacetal 156 [84]. Thus, two-step treatment of diol 155 under the established conditions provided spiroacetal 156 as a 2 1 mixture of epimers. 

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