Medium and Large -Heterocycle Formation via Allene Hydroamination with a Bimetallic Rh(II) Catalyst.

We report the synthesis of a 2-phosphinoimidazole-derived bimetallic Rh(II) complex that enables intramolecular allene hydroamination to form 7- to 10-member rings in high yield. Monometallic Rh complexes, in contrast, fail to achieve any product formation. We demonstrate a broad substrate scope for formation of various -heterocycles.