Regioselectively <i>N</i>-Methylated Azacalix[8]arene Octamethyl Ether Prepared by Catalytic Aryl Amination Reaction Using a Temporal <i>N</i>-Silylation Protocol

Abstract

[Structure: see text] A temporal N-silylation protocol in the catalytic aryl amination reaction has been devised to prepare nitrogen-bridged calixarene analogues. The protocol involves a smooth in situ N-silylation before aryl amination reaction, followed by spontaneous cleavage of the N-Si bond in the usual workup process, to furnish secondary aromatic amines as the cross-coupled product with no silyl group on the nitrogen atom. A successful application to the preparation of regioselectively N-methylated azacalix[8]arene is described, together with the crystallographic analysis.