Anionic Cascade Reaction Followed by Silylative Dieckmann Cyclization: A Straightforward Route to Tricyclic Fused Ring Systems Starting from Alkynyl Esters Tethered to Bicyclo[n.2.0]alkanones

The successive addition of sodium ethoxide and TBSOTf (or TMSOTf) to alkynyl esters tethered to bicyclo[ n .2.0]alkanones ( n = 3–5) promoted a domino anionic reaction and a Dieckmann condensation, respectively, which led to 5‐6‐5, 6‐6‐5, and 7‐6‐5 tricyclic fused ring systems. These systems represent relevant substructures of numerous bioactive compounds.