selectivity, and regioselectivity in relevant contexts. Expanding the scope of our strategy, we developed additional enantioselective transformations involving ligands, organocatalysts, and additives with fluxional chirality. We synthesized ligands with varied donor atoms for metal coordination and applied these in Lewis acid catalyzed Diels-Alder reactions, diethylzinc additions, and palladium-catalyzed allylic alkylations. In our work on organocatalysts, 4-(dimethylamino)pyridine-based catalysts provided high selectivities in reactions including kinetic resolutions and dynamic kinetic resolutions of biaryl compounds, and thiourea catalysts promoted highly enantioselective conjugate additions to nitroalkenes. Pioneering a novel application of additives in asymmetric catalysis, we employed pyrazolidinone-based additives with a stereogenic nitrogen to achieve enantioselectivity enhancements in Lewis acid catalyzed cycloadditions─an attractive approach using simply a small, achiral molecule to amplify stereoinduction.These asymmetric methods encompass significant variation in modes of catalysis, mechanistic pathways, means of enantioinduction, and spatial separation between static and fluxional chirality. Together, our results validate N-centered fluxional chirality as a useful phenomenon with significant versatility in asymmetric synthesis. With this foundation, the use of fluxional chirality at nitrogen is poised to become a more widely implemented strategy with new applications in enantioselective catalysis.
Renner et al. (Mon,) studied this question.