An efficient and practical strategy of nitrogen-centered radical mediated α-sulfonimidation of carbonyl compounds was established. The ketone α-sulfonimidation was initiated by a benzenesulfonimide radical generated from NFSI under the catalytic...

Five unknown labdane diterpenoids Stevelins A -E (1 -5), three known labdane diterpenoids (6 -8) and three labdane norditerpenoids (9 -11) were isolated from the Stevia rebaudiana. The structures were determined primarily via NMR spectroscopic data and HR-ESI-MS experiments. X-ray crystallography using CuK α radiation was used to determine the absolute configurations of 1, and the absolute configurations of 2-5 were deduced by electronic circular dichroism (ECD) calculations. The potential anti-atherosclerosis activities of all compounds were evaluated by measuring their inhibitory effects on the macrophage foam cell formation. As a result, most isolated compounds could significantly inhibit oxidized low-density lipoprotein (ox-LDL)-induced macrophage foam cell formation, which suggests that these compounds may be promising candidates in the treatment for atherosclerosis.