Asymmetric dihydroxylation of stachysterone C: Stereoselective synthesis of 24-epi-abuasterone

Article abstract of DOI:10.1016/S0040-4020(98)83015-9

Stachysterone C was synthesized from 20-hydroxyecdysone (20-ECD). Sharpless asymmetric dihydroxylation of this rare ecdysteroid using osmium tetroxide and a chiral ligand afforded 24-epi-abutasterone, another rare ecdysteroid, and its C-24 epimer, abutasterone. High diastereomeric excess of the former ecdysteroid was obtained when the chiral ligands dihydroquinidine 1,4-phthalazinediyl diether and dihydroquinidine 2,5-diphenyl-4,6-pyrimidinediyl diether were employed. The two C-24 epimeric ecdysteroids exhibited similar moulting hormone activity in the Musca bioassay. However, they were significantly less active than 20-ECD.