Abstract:

Conventional electronic circular dichroism (ECD) as well as optical rotation (OR) are not only one of the earliest and most powerful chiroptical methods for determining absolute configurations (AC) in solution, but they are also methods that have rapidly improved in term of better data acquisition and analysis. Furthermore, in the past two decades the ab initio methodologies for theoretical simulations of chiroptical properties have made a tremendous progress. The latter has greatly improved the interpretation of experimental ECD and OR spectra, as well as of more recently accessible vibrational CD data, towards determination of AC of even more structurally complex natural products. The lecture will highlight some basic concepts in ECD, VCD and OR methods regarding their applications for determination of AC, as well as the emerging awareness regarding the advantages of using simultaneously more than one chiroptical method for AC analysis. We will also discuss some recent stereochemical studies on AC of structurally diverse natural products. The examples will include the polyether marine toxin Gymnocin B, the cruciferous phytoalexin Brasicanal C, the alkaloid Actinophyllic acid, the irregular diterepene Anisotomenoic acid, some fungal and plant metabolites, such as, Scytolide, Phyllostin and Oxysporone, and some acyclic alcohols and aminoalcohols.