Pyrrolidinone-containing heterocycles are important scaffolds in natural products and highly relevant for the pharmaceutical industry. Although previous reaction processes have addressed the asymmetric synthesis of these heterocycles, the use of readily available, cheap and bench-stable precursors (such as α,β-unsaturated esters) is still of synthetic interest. Herein we present the isochalcogenourea-catalysed chemo- and enantioselective synthesis of pyrrolidinones (γ-lactams) in up to 95% yield, 95:5 dr and 94:6 er via a Michael addition/hydrolysis/lactamisation cascade. The corresponding Michael addition product could be isolated prior to hydrolysis and functionalised to generate a range of ester and amide products in up to 81% yield, > 95:5 dr and 98:2 er. In addition, a switch in chemoselectivity to obtain chromeno-pyrrolidines in up to 58% yield, > 95:5 dr and 99:1 er via a Michael addition/intramolecular Mannich reaction/lactonisation sequence was achieved. Strategic placement of an ortho-hydroxy group within the benzophenone imine moiety was used to increase imine electrophilicity via hydrogen bonding and therefore facilitate the intramolecular Mannich reaction.

Our group has recently introduced chiral isotelluroureas as a new class of Lewis base catalysts, which show increased nucleophilicity and basicity as compared to the lighter chalcogen-based congeners within the family of isochalcogenoureas. This short perspective article aims to introduce the readers to these novel catalysts which show promising reactivity profiles and allow for increased reaction rates, thus making them particularly appealing for applications where some of the established isothioureas or isoselenoureas may not be nucleophilic enough and thus reach their limits.

The behavior of higher-order radiative corrections due to initial state radiation in processes of electron-positron annihilation is analyzed. Numerical results for energies of future colliders are presented. Uncertainties of the known results on these corrections are estimated. A modified scheme for simultaneous exponentiation of pure photonic and non-singlet pair corrections is presented. Matching of the exponentiated results with the existing analytic higher-order calculations is constructed. A new subtraction scheme is suggested. The results obtained are important for increasing the relative accuracy of the theoretical description of processes that will be studied in future electron-positron colliders to a level of approximately 10^-5.