Diterpenoids: Natural Distribution, Semisynthesis at Room Temperature and Pharmacological Aspects‐A Decade Update

Abstract

Diterpenoids are a wide and structurally diverse class of natural products and secondary metabolites obtained from four isoprene units joined in a head‐tail fashion. It has been extensively investigated that a semisynthesis is an essential tool for enhancing the biological activity of starting natural products. Different diterpenoids have been employed as starting materials for the synthesis of bioactive semisynthetic derivatives at room temperature in this review. Energy plays a profound role in chemical transformations. However, according to the sixth principle of green chemistry, the most successful route to save energy is to develop strategies/protocols that are able enough to perform the reactions at ambient temperature. This review is aimed to offer an overview of natural distributions of diterpenoids, design, and semisynthesis of diterpenoids at room temperature, and highlights biological activities of semisynthetic derivatives for the first time from 2010–2019.

Applications of Norrish type I and II reactions in the total synthesis of natural products: a review

“…Unusual structural features of it such as complex hexacyclic structure with six stereogenic centers having dense oxygen functionalities as well as remarkable biological activity attracted the attention of the synthetic community [46][47][48][51][52][53]. The total synthesis of (-)-spiroxin C ( 14) begun with readily available tetralone (9), which was transformed to the essential photosubstrate (10). Naphthoquinone (10) was prone to undergo Norrish-type II intramolecular 1,5-hydrogen shift as a central step.…”

“…Synthetic studies of natural products with complex structures using Norrish photoreactions are very beneficial environmentally as classical thermal protocols require toxic, explosive materials, tedious, and long procedures frequently. The total synthesis of most of the molecules of natural origin and their analogues is one of the great challenges for organic synthesis due to their chemical diversity, and difficult stereochemistry [8][9][10][11][12][13][14]. As energy is essential for chemical conversions, this energy to an organic synthesis along with a total synthesis of natural products can be provided by light as a non-polluting powerful tool that enables the selective production of chemical bonds under mild reaction conditions with the help of photoredox catalyst.…”

“…So we need the total synthesis of natural products in confirming the hypothetical complex structures of secondary metabolites despite sophisticated analytical and spectroscopic instrumentation and techniques that are available presently. Moreover, total synthesis is also efficient to prepare rare bioactive secondary metabolites in the laboratory as various natural products are originated in small quantities from natural sources, especially those from higher plants and marine organisms [8][9][10][11][12][13][14].…”

Unprecedented diterpenoid dimers with soluble epoxide hydrolase inhibitory effect from Euphorbia fischeriana

“…Diterpenoids represent one of the most promising groups in natural products for drug discovery because of their wide range of biological activities and great structural diversity, resulting from various polycyclic skeletons. 1,2 Some of them have been developed as clinical drugs, such as paclitaxel obtained from Taxus brevifolia for the treatment of ovarian, esophageal, and breast cancer. 3 Ginkgolide B was isolated from Ginkgo biloba to act as a platelet-activating factor receptor antagonist.…”

Applications of Yamaguchi Method to Esterification and Macrolactonization in Total Synthesis of Bioactive Natural Products

“…Natural product chemistry has experienced wide growth, constructing secondary metabolite the subject of much interest as a majestic number of modern drugs have been obtained from natural sources. Bioactive natural products have played a key role in the drug development and discovery process; [8][9][10][11][12][13] mainly anticancer and antibiotic compounds are noticeably enriched with natural products. [8,[14][15][16] The total synthesis of bioactive secondary metabolites has a privileged position of trust to confirm the hypothetical complex structures of natural products despite sophisticated analytical and spectroscopic instrumentation and techniques that are available currently.…”