New approach to terpene syntheses

July 30, 2018, University of Basel
On the left, the around 1.4 cubic nanometer-large cavity within the molecular capsule is highlighted in blue. On the right, the cohesion of the capsule via hydrogen bonds (green dashed lines) is visible. Credit: University of Basel, Department of Chemistry

Terpenes are natural products that are often very difficult to synthesize in the laboratory. Chemists from the University of Basel have now developed a synthesis method that mimics nature. The decisive step takes place inside a molecular capsule, which enables the reaction. The findings were recently published in the journal Nature Catalysis.

Terpenes are the largest class of chemical compounds that are found in nature. They include, for example, many essential oils, steroids and clinically relevant substances such as the antimalarial drug artemisinin or the chemotherapy medication paclitaxel.

Despite increasingly refined synthesis methods, chemists have found it very difficult to synthesize these structurally complex compounds in the lab. The process often requires numerous, not always selective synthesis steps, and the yields tend to be low.

Nature points the way

The research group led by Professor Konrad Tiefenbacher from the University of Basel's Department of Chemistry has now developed a synthesis concept for terpenes copied from nature.

The decisive step takes place in the cavity of a spherical compound—known as a molecular capsule. The resorcinarene capsule used has been known about for around 20 years but its catalytic effect has only very recently been described, by Tiefenbacher and others. In organic solvents, the capsule forms itself from six smaller, ring-shaped compounds with the help of hydrogen bonds.

In a similar way to nature, the researchers led by Tiefenbacher begin with a starting material for the synthesis, which is enclosed by the capsule. The capsule environment then enables the formation of the terpene. In addition, control elements previously integrated into the precursor help avoid unwanted side effects and direct the transformation towards the desired product.

Proven applicability

The applicability of the concept was proven by the four-step of the product isolongifolene, with the formation of a ring-shaped terpene compound catalyzed by the capsule as the key step. This succeeded—when compared with conventional syntheses—in significantly fewer steps and with a good yield. Using labeled precursors and with the help of computer simulations, the Basel chemists were also able to clarify the reaction mechanism.

"Our next goal is to use capsules as an artificial enzyme in the creation of even more complex terpenes," says Professor Tiefenbacher. "In order to do so, we must learn to better control the spatial arrangement of the precursor within the , either by modifying the existing system or by developing new catalysts." This may open up new ways of synthesizing terpene that would otherwise not be readily accessible.

Explore further: Simple catalyst helps to construct complex biological scaffolds

More information: Qi Zhang et al, Sesquiterpene cyclizations catalysed inside the resorcinarene capsule and application in the short synthesis of isolongifolene and isolongifolenone, Nature Catalysis (2018). DOI: 10.1038/s41929-018-0115-4

Related Stories

Chemists suggest a new way to synthesize steroid analogs

November 15, 2017

Scientists from RUDN University and the Ivan Franko National University of Lviv have found a way to produce aromatic rings in organic compounds in three stages. These stages proceed successively in one-pot conditions and ...

New chemistry technique reproduces nature's elusive complexity

September 24, 2012

(Phys.org)—Scientists at The Scripps Research Institute have shown how to synthesize in the laboratory an important set of natural compounds known as terpenes. The largest class of chemicals made by living organisms, terpenes ...

A new nano-sized hexameric molecular capsule

November 10, 2017

Halonium ions used in this study, are well-known reaction intermediates and halogenating reagents in synthesis, but now they have been used as robust and stable structural units in molecular nanotechnology.

Recommended for you

Zapping a new approach to solar cells

August 13, 2018

A simple and fast microwave experiment with the common chemical element phosphorus at Flinders University has opened the prospect of more affordable and effective super-thin solar cells.

Hybrid catalyst with high enantiomer selectivity

August 9, 2018

A group of Japanese researchers has developed a technology to create a hybrid catalyst from simple-structured, commercially available rhodium and organic catalysts, which reduces chemical waste and produces molecules with ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.