Contemporary Synthetic Strategies towards Secosteroids, abeo-Steroids, and Related Triterpenes

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 Introduction 2 Cyclocitrinol 2.1 Li’s Synthesis of Cyclocitrinol 2.2 Gui’s Synthesis of Cyclocitrinol 3 Strophasterol 3.1 Heretsch’s Synthesis of Strophasterol A 3.2 Kuwahara’s Synthesis of Strophasterols A and B 4 Pleurocin A/Matsutakone and Pleurocin B 4.1 Heretsch’s Synthesis of Pleurocin A/Matsutakone and Pleurocin B 5 Aplysiasecosterol A 5.1 Li’s Synthesis of Aplysiasecosterol A 6 Glaucogenins C and D 6.1 Tian’s Syntheses of 5,6-Dihydro-glaucogenin C and Glaucogenin D 7 Physalin B 7.1 Sodeoka’s Synthesis of the DFGH Ring System of Physalin B 8 Limonin 8.1 Hirama’s Synthesis of (±)-Limonin 9 Schiglautone A 9.1 Ding’s Synthesis of (±)-atrop-Schiglautone A 10 Conclusion