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Beside showing that thermal radical reactions (reduction, Giese reaction) are efficient if bromo-/iodosugars are treated with NaBH3CN and 2,2″-azobisisobutyronitrile, we explored new initiation conditions on the basis of CuI salts (≤0.5 equiv.) supposed to produce radicals from organobromides through a set. This was confirmed, as at about 50 °C under an inert atmosphere acetobromoglucose was reduced to the rearranged 2-deoxyglucose and as N-allyl α-bromoamides reacted, depending on the conditions, either by reductive cyclization or atom-transfer radical cyclization. A related cyclization occurred upon using Cu(OAc)2. This and other assays showed the reduction by NaBH3CN of CuII salts, either added or formed in situ. Having both ionic and radical reactivity, NaBH3CN appears as a Janus reagent that may be useful for tin-free radical chemistry under mild and very simple conditions.

Thermal radical reactions (reduction, Giese reaction) are studied on halosugars and α-bromoamides.