Search

Steroids have long been sought after as synthetic targets. Their rearranged counterparts, though, have only recently received more attention, when isolation and biological testing programs revealed several molecular entities that were both structurally intriguing as well as biologically relevant. This review will highlight contemporary synthetic approaches towards the growing class of seco- and abeo-steroids and some related triterpenoid natural products.1 Introduction2 Cyclocitrinol2.1 Li’s Synthesis of Cyclocitrinol2.2 Gui’s Synthesis of Cyclocitrinol3 Strophasterol3.1 Heretsch’s Synthesis of Strophasterol A3.2 Kuwahara’s Synthesis of Strophasterols A and B4 Pleurocin A/Matsutakone and Pleurocin B4.1 Heretsch’s Synthesis of Pleurocin A/Matsutakone and Pleurocin B5 Aplysiasecosterol A5.1 Li’s Synthesis of Aplysiasecosterol A6 Glaucogenins C and D6.1 Tian’s Syntheses of 5,6-Dihydro-glaucogenin C and Glaucogenin D7 Physalin B7.1 Sodeoka’s Synthesis of the DFGH Ring System of Physalin B8 Limonin8.1 Hirama’s Synthesis of (±)-Limonin9 Schiglautone A9.1 Ding’s Synthesis of (±)-atrop-Schiglautone A10 Conclusion

The first chemical synthesis of glaucogenin D, a 13,14:14,15-disecopregnane steroid with potential antiviral activity, has been accomplished in 12 steps from a hirundigenin-type intermediate. The present route would also be amenable to the synthesis of natural and unnatural glaucogenin derivatives for SAR studies.

Three new glycosides named cynaversicoside C, D and E with glaucogenin D as the aglycone were isolated from the Chinese crude drug ‘Pai-Wei’, Cynanchum versicolor . Their structures were determined on the bases of combined physio-chemical evidence as glaucogenin D:3- O -β- d -thevetopyranoside; glaucogenin D:3- O -β- d -cymaropyranosyl-(1→4)-α- l -diginopyranosyl-(1→4)-β- d -thevetopyranoside; glaucogenin D:3- O -β-glucopyranosyl-(1→4)-β- d -cymaropyranosyl-(1→4)-α- l -diginopyranosyl-(1→4)-β- d -thevetopyranoside.

Three new glycosides named cynapanosides A (1), B (2), and C (3) which contain a new aglycone, glaucogenin D (10), were isolated from Cynanchum paniculatum, in addition to the known compounds, cynatratoside B (5) and 3β, 14-dihydroxy-14β-pregn-5-en-20-one (13). Their structures were elucidated by spectroscopic and chemical methods. The results led us to propose a structure revision of glaucogenin B (11).