Direct formation of cyclic sulfates utilising hypervalent iodine species and sulfur trioxide adducts

PhIO reacts with SO3·DMF at 0°C to form an active sulfating reagent; subsequent addition of alkenes results in the direct formation of cyclic sulfates in moderate to good yield (35–75%). Terminal, 1,1-disubstituted and cyclopentenes participate in the reaction which is technically very straightforward to carry out.