1.
J Org Chem
; 88(13): 8310-8315, 2023 Jul 07.
Article
in English
| MEDLINE
| ID: mdl-37339270
ABSTRACT
Pillar[6]arenes are established as crucial building blocks in supramolecular chemistry; however, they can be difficult to synthesize, particularly in the absence of large solubilizing substituents. In this work, we explore variability in literature syntheses of pillar[6]arene derivatives and suggest that the outcome is dependent on whether oligomeric intermediates stay in solution long enough for the thermodynamically favorable macrocyclization to occur. We demonstrate that in a previously capricious BF3·OEt2-mediated procedure, ≤5 mol % of a Brønsted acid can slow down the reaction to favor macrocycle formation.