Pd(II)‐Catalyzed Conversion Of <i>N</i>‐Troponyl‐Amino Acid Derivatives Into Cationic Troponyl‐Oxazolidines

Abstract Benzoxazole and benzoxazolidine are constituents of various bioactive natural/synthetic molecules comprising benzenoid aromatic residue. However, non‐benzenoid aromatic scaffolds such as tropone and tropolone are also found in natural products. This report describes the synthesis of unusual cationic troponyl‐oxazolidine derivatives from N ‐troponyl‐amino acids/peptides by Pd(II)‐catalyzed transformation. X‐ray studies confirm the formation of the first tropylium cation annelated oxazolidine structures and support the formation of unique supramolecular self‐assembly structures owing to the H‐bonding. The CV studies of new tropylium cations reveal their reduction potential ca −1.2 V. Hence, cationic troponyl‐oxazolidinyl amino acids/peptides could be promising analogs of benzoxazolidine for the development of therapeutic drugs.