Novel indium-mediated radical cyclization reactions of aliphatic iodoalkynes have been studied. Treatment of iodoalkynes with a catalytic amount of In (0.1 equiv) and I2 (0.05 equiv) promotes atom-transfer 5-exo cyclization to give five-membered alkenyl iodides. In contrast, reaction with In (2 equiv) and I2 (1 equiv) yields reductive 5-exo cyclization products via the same 5-exo cyclization. Both
An efficient and convenient method for the synthesis of 2-deoxy-2-iodo-O-glycosides from tri-O-acetyl-D-glucal with various alcohols by using I(2)-Cu(OAc)(2) is described. The 21 examples of corresponding glycosides were obtained in high yields, with good anomeric selectivity.