Recent Developments in Selected Sesquiterpenes: Molecular Rearrangements, Biosynthesis, and Structural Relationship among Congeners

Recent developments in selected sesquiterpenoids are reviewed for the past one decade (2005–2017) with special reference to Mechanisms of multistep molecular rearrangements of some sesquiterpenes or derivatives based on isotopic labeling studies and extensive spectroscopic analysis such as molecular rearrangement of acetyl cedrene to cedrene follower, acid catalyzed rearrangement of moreliane-based triketone, synthesis of (−)-iso - comene and (−)-triquinane by acid-catalyzed rearrangement of (−)-modhephene, Total synthesis of (+)-cymbodiacetal, BF 3 catalyzed molecular rearrangements of mono epox- ides of α- and β-himachalenes, santonic acid: Zn-HCl-ether reduction. Insights into bio synthesis of albaflavenone, caryol-1(11)-ene-10-ol, (+)-koraiol, pogostol, patchouli alcohol and valerenadiene are discussed. Congeners for probing structure-biosynthetic relation -ship. This approach is discussed with the availability of very interesting results on the isolation of highly oxygenated secondary metabolites from endophytic fungi, Xylaria sp. synthase, a terpene synthase catalyzing a unique chemical cascade in the biosynthesis of biologically active