Photo‐induced three‐component reaction for the construction of α‐tertiary amino acid derivatives

Abstract The synthesis of α‐tertiary amino acids (ATAAs), which are pivotal components in natural metabolism and pharmaceutical innovation, continues to attract significant research interest. Despite substantial advancements, the pursuit of a facile, versatile, and resource‐efficient methodology remains an area of active development. In this work, we introduce a visible light‐triggered three‐component reaction involving readily available nitrosoarenes, N ‐acyl pyrazoles, and allyl or (bromomethyl)benzenes under mild conditions. This approach enables the straightforward assembly of a wide array of ATAA derivatives (42 examples) in commendably high yields (up to 89 %). Mechanistic investigations elucidate that the reaction proceeds through a dehydration condensation between nitrosoarenes and N ‐acyl pyrazoles to generate ketimine intermediates. This is followed by a light‐driven halogen atom transfer (XAT) process and a radical addition, culminating in the formation of the desired products. The approach showcases excellent functional group compatibility and late‐stage derivatization potential, offering new insights and avenues for the synthesis of ATAA analogs.