3 Dec 2013
Prof Paolo Melchiorre, one of the speakers at our Asymmetric Organocatalysis conference, speaks to SCI ahead of the event in April 2014.
Which are the most notable discoveries in organocatalysis in the past five years, in your opinion?
Organocatalysis has reached a level of reliability and sophistication that has allowed researchers to combine this technique with other powerful strategies for molecule activation. This approach has allowed previously unattainable synthetic problems to be solved. One such example has been provided by the merging of aminocatalysis and photoredox catalysis. The concept, first conceptualised by Dave MacMillan's group, has attracted much attention for the ability to solve long-standing problems in asymmetric catalysis. This has also provided new avenues for academic thoughts, as testified by the recent explosion of interest in the development of light-driven reactions and photoredox-based radical processes.
Organocatalysis has also been successfully combined with metal-based chemistry, thus enriching the synthetic toolbox available to modern organic chemists. Recent exciting findings by Ben List have also shown the possibility for a large-scale approach of organocatalysis; chiral organic molecules have been immobilised on a nylon textile, an approach which has allowed the catalyst to be recycled more than 200 times without loss of enantioselectivity.
Which ones of your group's discoveries are you most proud of?
I generally reply to the question saying that my most exciting discovery to date is always the last one (or, better still, the next one).
Thus, I chose the recent study where we reported that readily available chiral organic catalysts, with well-known utility in thermal asymmetric processes, can also confer a high level of stereocontrol in synthetically relevant photochemical process driven by visible light. In this study, we have found a bridge (donor-acceptor interactions) to connect two powerful fields of molecule activation: asymmetric organocatalysis and photochemistry, challenging the current perception that photochemistry is too unselective to parallel the impressive levels of efficiency reached by the asymmetric catalysis of thermal reactions.
Have you ever felt that organocatalysis was being overrated?
Not at all, and overrated by whom? My opinion is that organocatalysis has provided the opportunity to solve difficult problems connected with the preparation of chiral molecules using a simple, reproducible, and easy approach. In a certain way, the impressive interest generated by the field can be due to the fact that organocatalysis is a 'democratic' research line: since it uses inexpensive substrates and catalysts, and it does not need sophisticated and costly equipments, organocatalysis has been chosen by many groups with a limited research budget at hand, including young researchers at the beginning of their career path.
Why would you encourage a young person to start a PhD or postdoc in organocatalysis?
I generally encourage young students to do what they like the most - the topic is not that important, it can be asymmetric organocatalysis, or material science, or total synthesis. What is important is that they continuously challenge themselves trying to do their best, every day, so to become good researchers while understanding the ethical implication to be scientists.
For postdocs the situation is different, since they need to complement their skills. Organocatalysis can provide a nice addition to their already established background, since it now constitutes a very effective and established way for the preparation of chiral molecules.
Armando Carlone
Chirotech Technology Centre - Dr. Reddy's
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