Three Benzynes and the Ynolate
Regioselective One-Pot Synthesis of Triptycenes via Triple-Cycloadditions of Arynes to Ynolates.
Angew. Chem. Int. Ed. 2017;
15 February 2017 (online)
The triptycene structure is a remarkable scaffold that is frequently employed in functional materials as a result of its three dimensional, noncompliant structures and the interstitial space around the molecule. Most syntheses are based on a Diels–Alder cycloaddition between anthracene and an aryne. The authors describe a one-pot synthesis of triptycenes that proceeds through three cycloadditions of arynes to ynolates.
The approach of formally inserting three arynes into an alkyne is a new and powerful way to obtain both simple and substituted triptycenes. Calculations provide an insight into the mechanism and explain the high regioselectivity (head-to-head-to-head).