Evolution of Strategies in Protecting‐Group‐Free Synthesis of Natural Products: A Recent Update

The synthesis of complex natural products must be realized with high economy and efficiency, contributing largely to sustainable development in synthetic organic chemistry. The new strategies should adopt protecting‐group‐free approaches enabling step‐economy and thereby enhancing efficiency. Various approaches based on chiral pool, auxiliary‐based methods, cascade, biomimetic, enzymatic and photocatalytic used in total synthesis of natural products and following the PGF‐criteria over the last two years (2018–2019) have been reviewed here. These should guide sustainable synthesis of natural products in the future. This review article highlights the recently achieved efficient total syntheses of many natural products based on chiron, auxiliary, cascade, biomimetic and photocatalytic approaches, as well as protecting‐group‐free strategies, leading to overall economy and efficiency in synthesis.