Modular Total Synthesis of iso-Archazolids and Archazologs

Total Synthesis and Determination of Absolute Configuration of Cryptorigidifoliol G

The first asymmetric total synthesis of (1S,5R,7S)-cryptorigidifoliol G and (1S,5R,7R)-cryptorigidifoliol G of the proposed natural product was achieved. The key steps in the synthesis involved Keck-Maruoka allylation, our own developed protocol for the construction of the trans-2,6-disubstituted dihydropyran, iodolactonization, cross-metathesis, Prins cyclization, and cis-Wittig olefination reaction. A comparison of the NMR as well as analytical data and thorough analysis of the 2D NMR suggested that the absolute stereochemistry of the proposed natural product is (1S,5R,7S)-cryptorigidifoliol G.

Steglich esterification: A versatile synthetic approach toward the synthesis of natural products, their analogues/derivatives

The exploitation of natural products and their analogues in the field of pharmacology has been regarded as of great importance. It can be attributed to the fact that these scaffolds exhibit diverse chemical properties, distinct biological activities and zenith specificity in their biochemical processes, enabling them to act as favorable structures for lead compounds. The synthesis of natural products has been a crafty and hard-to-achieve task. Steglich esterification reaction has played a significant role in that area. It is a mild and efficient technique for constructing ester linkages. This technique involves the establishment of ester moiety via a carbodiimide-based condensation of a carboxylic acid with an alcohol, thiol or an amine catalyzed by dimethyl aminopyridine (DMAP). Specifically, labile reagents with multiple reactive sites are esterified efficiently with the classical and modified Steglich esterification conditions, which accounts for their synthetic utility. This review encloses the performance of the Steglich esterification reaction in forging the ester linkage for executing the total synthesis of natural products and their derivatives since 2018.