Metal-catalysed C–H bond functionalisation has had a significant impact on how chemists make molecules. Translating the methodological developments to their use in the assembly of complex natural products is an important challenge for the continued advancement of chemical synthesis. In this tutorial review, we describe selected recent examples of how the metal-catalysed C–H bond functionalisation has been able to positively affect the synthesis of natural products.

Recent developments in natural product synthesis using metal-catalysed C–H bond functionalisation

Antioxidant Potential of Ferulic Acid

Occurrence, Biogenesis, and Synthesis of Biologically Active Carbazole Alkaloids

2.1.8. Michael Reaction 2245 2.1.9. Others 2247 2.2. Cyclization Reactions 2248 2.2.1. Carbon Diels−Alder Reactions 2248 2.2.2. Aza-Diels−Alder Reactions 2252 2.2.3. Other Hetero-Diels−Alder Reactions 2255 2.2.4. Ionic Diels−Alder Reaction 2256 2.2.5. 1,3-Dipolar Cycloadditions 2256 2.2.6. Other Cycloaddition Reactions 2258 2.2.7. Prins-type Cyclization 2259 2.3. Friedel−Crafts Acylation and Alkylation 2259 2.4. Baylis−Hillman Reaction 2263 2.5. Radical Addition 2264 2.6. Heterocycle Synthesis 2267 2.7. Diazocarbonyl Insertion 2270 3. C−X (X ) N, O, P, Etc.) Bond Formation 2271 3.1. Aromatic Nitration and Sulfonylation 2271 3.2. Michael Reaction 2272 3.3. Glycosylation 2273 3.4. Aziridination 2275 3.5. Diazocarbonyl Insertion 2276 3.6. Ring-Opening Reactions 2277 3.7. Other C−X Bond Formations 2280 4. Oxidation and Reduction 2280 4.1. Oxidation 2280 4.2. Reduction 2281 5. Rearrangement 2283 6. Protection and Deprotection 2285 6.1. Protection 2285 6.2. Deprotection 2288 7. Polymerization 2291 8. Miscellaneous Reactions 2291 9. Lanthanide(II) Triflates in Organic Synthesis 2295 10. Conclusion 2295 11. Acknowledgment 2295 12. References 2295

Rare-earth metal triflates in organic synthesis

https://chemistry.mdma.ch/hiveboard/rhodium/pdf/piper.phytochemistry.pdf

Phytochemistry of the genus Piper

Alkaloids of Piper longum Linn—I : Structure and synthesis of piperlongumine and piperlonguminine

Occurrence of geissoschizine and other minor biogenetically related alkaloids in Rhazya stricta

The electrophilic substitution reaction of indole with acetone in the presence of boron trifluoride has been followed and the structures of two of the three products isolated have been established. The structure of compound (1), dimer II, was determined by X-ray diffraction methods as crystals from methanol were monoclinic, space group Cc, and had cell parameters a= 13.383(2), b= 14.064(2), c= 11.638(4)A, β= 114.74(2)°, Z= 4. The structure was refined to a final R value of 0.068.

Lewis-acid-induced electrophilic substitution in indoles with acetone. Part 2

To study the antifertility effect of an extract (alcoholic) of the leaf-stalk of Piper betle Linn., one set of experiments with two different doses in Swiss male albino mice were evaluated. Initially, 500 mg of the leaf-stalk extractive for 30 days and then 1000 mg for next 30 days/animal/day/kg body weight were administered orally. The extract reduced fertility to 0% within 60 days. Suppression of cauda epididymal sperm count and motility (p ,0.05) was observed. Biochemical parameters did not show any marked alterations in testosterone content in serum nor 17b-hydroxysteroid dehydrogenase (17b-HSD) activity in testes although fructose content in seminal vesicles was reduced as are the weights of reproductive organs. The cholesterol content in testes increased, although not appreciably. After cessation of drug (plant extract) treatment, the altered parameters recovered. Results suggest that the contraceptive effect of the extract of leaf-stalk of Piper betle Linn. is mainly on the maturation process of spermatozoa in epididymides without influencing hystemic hormonal profiles. Withdrawal of the extract restored all altered parameters including organ weights and fertility after 60 days. © 2001 Elsevier Science Inc. All rights reserved.

Asima Chatterjee

Papers

Alkaloids of Piper longum Linn—I : Structure and synthesis of piperlongumine and piperlonguminine

Occurrence of geissoschizine and other minor biogenetically related alkaloids in Rhazya stricta

Lewis-acid-induced electrophilic substitution in indoles with acetone. Part 2

Original research article The reversible antifertility effect of Piper betle Linn. on Swiss albino male mice

The reversible antifertility effect of Piper betle Linn. on Swiss albino male mice