Sulfanyl Radical-Induced Cyclization of Linalyl Acetate to the Iridane Skeleton: A Short Synthesis of (±)Dehydroiridomyrmecin

Sulfanyl radicals promote radical cyclization both in linalyl acetate (2) and its derivative 3, leading highly selectively to monoterpenoids with an iridane skeleton. We have investigated the addition of different sulfanyl radicals such as PhS•, 4NO2C6H4S• and PhCH2CH2S• and found that the latter radical produces the best results (87-93%). Natural iridoid dehydroiridomyrmecin (1) at an overall yield of 28% was synthesized in four steps using this method.