The reductive Pauson–Khand reaction (PKR) of tethered vinyl silanes likely proceeds as usual to the bicyclopentenones 2, but rapid loss of the allylic silane initiates a fragmentation process culminating in propargylic carbon reduction. Damp nitrile solvents are crucial for efficient reaction, and under dry conditions additional products are obtained including dimerized cyclopentadienones and 5-(1-amino-alkylidine) cyclopentenes. Solvent ...
