Total Syntheses of (+)-Alexine and Related Alkaloids
Total Syntheses of (–)-7-epi-Alexine and (+)-Alexine Using Stereoselective Allylation: I.-S. Myeong, C. Jung, W.-H. Ham
Synthesis 2019, DOI: 10.1055/s-0037-1611566
(+)-Alexine is a naturally occurring pyrrolizidine alkaloid, whose isolation was reported in 1988. Considered a sugar-mimic, owing to the presence of four hydroxy groups and a nitrogen atom that replaces the carbohydrate ring oxygen, (+)-alexine and structurally related congeners have attracted considerable interest due to their biological properties, which include a potent inhibitory activity toward glycosidases, as well as antiviral and antiretroviral effects. Recently, the group of Professor Won-Hun Ham from Sungkyunkwan University (Republic of Korea) has reported a new total synthesis of this molecule and of the related compound (–)-7-epi-alexine.
Professor Ham said: “Aiming to synthesize biologically active and useful compounds, we have developed novel chiral oxazoline and oxazine building blocks. With these oxazolines and oxazines, we have synthesized the polyhydroxylated alkaloids containing more than three contiguous stereogenic centers. In this manuscript, we described our synthetic efforts which led to a concise and stereocontrolled total syntheses of (–)-7-epi-Alexine and (+)-slexine.”