Study one established the 'conventional' cycloaddition reaction pathway via I-I•••O=C activated MVK, proceeded via TS-a-1' with a free energy barrier of 20.9 kcal mol -1 (Figure ) and could, ultimately, react with cyclohexadiene to generate 7. The second study showed that the free energy barrier to activating the carbon-carbon double bond in MVK through a I-I ••• interaction was 2.1 kcal mol -1 lower, or 18.8 kcal mol -1 , than the activated carbon-oxygen double bond (cf. I-I•••O=C, 20.9 kcal mol -1 ) of MVK. Legault and colleagues recently undertook a DFT study to better understand how iodine prefers to activate -C=C of methyl acrylate rather than C=O in its Michael addition reaction with pyrrolidine 8t . Our finding fits with their results. The distance between the two iodine atoms in TS-a-1 (2.92 Å) is longer than in TS-a-1' (2.75 Å), and IRC calculations on TS-a-1 confirmed MVK reacts with 1,3cyclohexadiene via I-cation transfer from iodine onto the C=C of the ,-unsaturated ketone. IRC calculation of TS-a-1 revealed that this reaction proceeds in a stepwise fashion, with the I + transferring from I2 to methyl vinyl ketone 6 during the formation the first C-C bond, generating Int-a-1 (Figure ) 8s . The resulting Int-a-1 then dissociates into the more stable Int-a-2 and an iodine anion. Initiating a mass spectroscopy study we sought evidence for the formation of one or more of the key intermediates in the computed potential energy map outlined in Figure . Gratifyingly, the analogue of key intermediate Int-a-2 was detected using high-resolution mass spectrometry (Figure ) this, we suggest, supports our proposition that I + transfer facilities formation of important intermediates on route to the final product.