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

Ortho -functionalization of pillar[ n ]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 ortho to the oxime functionality in pillar[4]arene[1]benzoquinone monoxime ( 1 ) via addition of Grignard reagents. The described method enables the creation of various mono- ortho -alkyl/aryl-substituted pillar[5]arene derivatives that were previously inaccessible.