ABSTRACT A mild and efficient 3+2 cyclization of α ‐bromohydroxamates with 4‐benzylidene‐pyrazolones is reported herein for the rapid assembly of spiro‐pyrrolidinones. Broad substrate scope, excellent functional group tolerance, and successful gram‐scale demonstration highlight the synthetic utility of this protocol. This method offers a straightforward and scalable approach to densely functionalized spirocyclic architectures.
Xiang et al. (2026) studied this question.