Chemists are using invisible electrostatic forces—the same attraction that binds table salt—to control single-electron reactions that have long resisted precise manipulation. Most chemical reactions shuffle electrons in pairs, but radical reactions move them one at a time, making them difficult to steer. This matters because radical reactions can build complex molecular structures with "handedness" (chirality), a property critical for pharmaceuticals, agrochemicals, and advanced materials. Existing methods for controlling handedness in two-electron reactions often fail for radicals. The researchers propose a fundamentally different approach: instead of relying on covalent bonds to hold reactants in place, they will exploit ion pairing—the electrostatic attraction between charged molecules and their oppositely charged partners. In many photoredox catalytic cycles, these counterions are ignored; the team believes they can be the key to unlocking enantioselectivity. If successful, this work would open new routes to synthesising single-handed versions of molecules that are currently inaccessible or require wasteful multi-step processes. The project targets four specific classes of radical transformations with no existing asymmetric methods. This is fundamental science—the immediate payoff is a deeper understanding of how to control radical chemistry, not a commercial product. But history shows that new catalytic strategies often become the hidden engines behind cleaner drug manufacturing, more efficient agrochemicals, and novel materials.
View original technical description
Radical reactions, in which electrons move singly rather than in pairs, have seen an immense pace of development in recent years. These exciting developments, many of which produce stereocentres, have served to highlight the ongoing challenge of rendering radical reactions enantioselective. Whilst many of the key enantiocontrol strategies from the two-electron world have been applied, these are ineffective in many situations and each strategy possesses specific limitations. We are broadly interested in an approach to catalysis that utilises attractive non-covalent interactions between catalyst and substrate to draw the two close and better exercise control. Particularly, ion-pairing is one of the most fundamental and powerful non-covalent interactions but is frequently underexplored by synthetic chemists as a controlling force, perhaps due to concerns regarding directionality and predictability. However, we believe that they present unique opportunities to exert selectivity control where conventional strategies fail. In this proposal we outline an ambitious program which will apply innovative and unexplored ion-pairing strategies to control enantioselectivity in a variety of important radical chemistries for which there are no or limited existing methods for imposing control. In catalytic cycles involving photoredox catalysis, whilst charge is usually appropriately indicated on intermediates, the associated counterion is rarely depicted or even attempted to be tracked in most reports. We believe that, far from being insignificant, counterions can play crucial roles in the control of enantioselectivity - in a catalytic cycle where there is little scope for leveraging existing modes of asymmetric catalysis, the counterion can provide the key. This proposal consists of four "challenge areas", as defined in the four Work Plans. These represent important and topical classes of radical transformations that have little or no precedent to be carried out asymmetrically using existing approaches. If the approaches outlined herein can be proven viable then there are numerous other reaction types to which they can be applied and we hope that this may open new horizons in the field.
Plain English summaries and category classifications on this site are generated by AI and may not perfectly reflect the original research.
Is something wrong? Let us know