High-yielding synthesis of deepened cavitands bearing picolyl moieties on the upper rim

Conventional high-yielding reactions (such as etherification, condensation reactions) and palladium-catalysed aminocarbonylation served as highly efficient synthetic tools for the synthesis of novel cavitands bearing Schiff-base and carboxamide/2-ketocarboxamide functionalities, respectively. In this way, two families of deepened cavitands with related structures possessing 2-, 3- and 4-picolylamine moieties on the upper rim have been synthesised. Unexpectedly high chemoselectivities towards tetracarboxamides and tetrakis(2-ketocarboxamides) have been observed. The aminocarbonylation of tetraiodocavitand as an iodoaromatic substrate proved to be highly selective in two aspects: (i) no substantial formation of either the mono-, di- or trifunctionalized products was observed and (ii) no 'mixed' products possessing both carboxamide and 2-ketocarboxamide fragments, due to selective simple and double carbon monoxide insertion, were detected.