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Photocatalysis to crop protection: asymmetric cascades for chiral heterocycles

Periodic Reporting for period 1 - PHOTOCHIRO (Photocatalysis to crop protection: asymmetric cascades for chiral heterocycles)

Reporting period: 2018-03-01 to 2020-02-29

What is the problem/issue being addressed?

As the continually rising levels of global consumption challenge the Earth’s capacity for production, chemistry will play a key role in the discovery of new technologies to support our future. Fundamental chemical research in agrichemistry is essential to develop a robust approach to crop protection and plant growth. One current challenge when developing novel molecular candidates, for both agrichemical and pharmaceutical industries, is efficient access to unpatented chemical space around biologically privileged scaffolds. Achieving this necessitates moving away from the “flat” heteroaromatic structures often associated with active ingredients. However, access to these chiral molecules bearing saturated heterocyclic scaffolds, with well-defined three-dimensional architecture, is a great challenge.

Why is it important for society?

The methodology developed during the project will impact crop protection R&D by providing access to novel chiral building blocks.

This project has brought new career possibilities by providing the fellow with expertise in asymmetric catalysis and photochemistry. The project offered opportunities in the academic and private sector due to the network of contacts and skills set that the involved researcher obtained throughout the project. PHOTOCHIRO has a particularly strong link to Knowledge and Technology Transfer (KTT), crucial for increasing the competitiveness of the European Economic Area (EEA).

What are the overall objectives?

The main goal of PHOTOCHIRO is to synthesize biologically relevant chiral scaffolds by means of cascade processes that combine enantioselective organocatalysis and photochemistry, two powerful strategies of modern chemical research with extraordinary potential for sustainably preparing organic molecules.

Specifically, the primary aims of the PHOTOCHIRO project have been:

1. Develop enantioselective aminocatalytic cascade processes to rapidly synthesise chiral saturated heterocycles with high enantiopurity. The cascades have been designed by combing the ground-state and excited-state reactivity of chiral aminocatalytic intermediates.

2. Conduct biological screening of the resulting chemical library, to demonstrate the applicability of the methodology to industrial R&D.
Two new synthetic organic methodologies have been developed and made (or will soon be made) publicly available through open-access peer-reviewed publication as a result of this project. The first entails a photochemical enantioselective, organocatalytic reaction of organic acids, alkenes and enals. The second is a general photoredox catalyst-mediated enantioselective organocatalytic conjugated addition of radical to enals, which was implemented in a library synthesis of enantioenriched chiral piperidines.
The novel concepts in PHOTOCHIRO have led to high impact publications that change the way synthetic chemists think about organocatalytic processes, by incorporating light-induced steps into the cascade framework. Considering the variety of different chiral heterocyclic compounds with biologically active properties, this methodology will impact crop protection R&D by providing access to novel chiral building blocks.

The project has opened the way for future collaborations between the academic and private sectors, having a great potential to contribute to the excellence and economy of European Science because Knowledge and Technology Transfer makes a significant contribution to economic competitiveness.
Figure from first publication showing the enantioselective catalytic radical cascade reaction.