https://www.selleckchem.com/products/jhu-083.html Many natural products have intriguing biological properties that arise from their fascinating chemical structures. However, the intrinsic complexity of the structural skeleton and the reactive functional groups on natural products pose tremendous challenges to chemical syntheses. Semi-synthesis uses chemical compounds isolated from natural sources as the starting materials to produce other novel compounds with distinct chemical and medicinal properties. In particular, advancements in various types of sp3 C-H bond functionalization reactions and skeletal rearrangement methods have contributed to the re-emergence of semi-synthesis as an efficient approach for the synthesis of structurally complex bioactive natural products. Here, we begin with a brief discussion of several bioactive natural products that were obtained via a semi-synthetic approach between 2008 and 2015 and we then discuss in-depth contemporary advancements in the semi-synthesis of bioactive terpenoids and steroids reported during 2016-2020.A practical and environment-friendly methodology for the construction of β-keto sulfones through visible-light induced direct oxysulfonylation of alkenes with sulfonic acids at ambient temperature under open-air conditions was developed. Most importantly, the reaction proceeded smoothly without the addition of any photocatalyst or strong oxidant, ultimately minimizing the production of chemical waste.Copolymerization is an effective approach to tailor the thermal and structural properties of liquid crystalline polymer materials, which is essential for various applications. In this work, two series of polynorbornene copolymers, A-r-B and A-r-C, with the biphenyl mesogenic side group at different substituent positions were synthesized via ring-opening metathesis polymerization in various compositions. The corresponding homopolymers A and C are liquid crystalline polymers, exhibiting an oblique columnar structure (Colob