<i>Ortho</i>-Functionalization of Pillar[4]arene[1]benzoquinone Monoxime via Selective 1,4-Addition of Grignard Reagents

<i>Ortho</i>-functionalization of pillar[<i>n</i>]arenes has been a formidable challenge, partially due to the fragility of their macrocyclic skeletons. In this concise report, we describe a facile synthetic method for monoarylation/alkylation at the position <i>ortho</i> to the oxime functionality in pillar[4]arene[1]benzoquinone monoxime (<b>1</b>) via addition of Grignard reagents. The described method enables the creation of various mono-<i>ortho</i>-alkyl/aryl-substituted pillar[5]arene derivatives that were previously inaccessible.