Flash Communication: Carbanion Translocation via Intramolecular 1,2-Proton Transfer for One-Carbon Expansion of Lanthanide Metallacycles

Kai Suo^#, Yibo Liang^#, Shuangji Song, Wei Liu*, and Wen-Xiong Zhang*

Organometallics 2026, 45, XXXXX–XXXXX. (^#Authors contributed equally)

https://doi.org/10.1021/acs.organomet.5c00515

Intramolecular hydrogen transfer represents one of the most fundamental and ubiquitous processes in both chemical and biological transformations. Here, we introduce a rare intramolecular 1,2-proton transfer within lanthanide metallacycles proceeds without external shuttles. The transformation converts five-membered lutetacyclopentenes into six-membered rings through a formal 1,2-proton transfer achieved via sequential 1,5- and 1,4-proton shifts. DFT calculations reveal that the Lu–C bond acts as an internal proton relay, preorganizing the transfer trajectory and lowering the barrier. Isolation of a ligand-stabilized intermediate further substantiates the proposed stepwise mechanism.