Total Synthesis Strategies for Daphniphyllum Alkaloids

The Daphniphyllum alkaloids constitute one of the most structurally intricate families of natural products, characterised by densely functionalised polycyclic frameworks that incorporate multiple contiguous quaternary centres and diverse ring sizes ranging from five- to nine-membered motifs. Total synthesis efforts have focused on convergent assembly of key ring systems, exploitation of cascade or biomimetic sequences to reduce step count, and the application of modern chiral catalysis to access complex stereochemical arrays. Major strategic themes include transition-metal-mediated ring-forming reactions, samarium(II)-promoted cyclisations, one-pot oxidative cycloadditions, and desymmetrisation of simple precursors to establish stereochemical complexity early in the route. Recent approaches have moved towards greater step efficiency through tandem processes, increased use of computational design to predict reactive conformations, and elaboration of modular building blocks that can be diversified en route to multiple subfamilies. These synthetic advances not only demonstrate new bond-forming logic for constructing challenging carbocycle arrays but also open access to material for biological evaluation, thereby enhancing the prospects for therapeutic development of these bioactive alkaloids.

Research from Nature Portfolio

Recent studies have achieved the first enantioselective total synthesis of a yuzurimine-type member of this family. Central to this milestone was a highly regioselective palladium-catalysed hydroformylation that forged a key aldehyde moiety, followed by a samarium(II)-mediated pinacol coupling to unite two fragments and establish adjacent quaternary centres. A one-pot sequence combining Swern oxidation with a ketene dithioacetal-based Prins reaction then constructed an additional ring and set multiple stereocentres in a single operation. This route represents a paradigm for integrating transition-metal catalysis and reductive cyclisation in a concise enantioselective synthesis of the most complex yuzurimine skeletons to date, and it sets the stage for extension to related subfamilies.

Total Synthesis Strategies for Daphniphyllum Alkaloids publication trend

The graph below shows the total number of articles in total synthesis strategies for daphniphyllum alkaloids across all publications each year (not limited to Nature Index journals).

Technical terms

Enantioselective synthesis: A synthetic process that preferentially forms one enantiomer of a chiral molecule over its mirror image.

Hydroformylation: A catalytic reaction that adds a formyl group and a hydrogen atom across a carbon–carbon double bond to generate aldehydes.

Pinacol coupling: A reductive dimerisation of carbonyl compounds, typically aldehydes or ketones, to produce vicinal diols.

Desymmetrisation: A strategy that converts a symmetrical molecule into an asymmetrical product by selective reaction at one of two or more identical sites.

Spirocyclisation: A ring-forming process that constructs a spirocyclic junction by linking two carbon centres from a single precursor, often via radical or ionic intermediates.

References

1. Asymmetric total synthesis of yuzurimine-type Daphniphyllum alkaloid (+)-caldaphnidine J. Nature Communications (2020).
2. Enantioselective Total Synthesis of (−)-Himalensine A via a Palladium and 4‑Hydroxyproline Co-catalyzed Desymmetrization of Vinyl-bromide-tethered Cyclohexanones. Journal of the American Chemical Society (2023).
3. Synthetic studies toward longeracemine: a SmI 2 -mediated spirocyclization and rearrangement cascade to construct the 2-azabicyclo[2.2.1]heptane framework. Chemical Science (2020).