Solid-Phase Synthesis of Cyclohexadienyl Amides

Significance

Iron-mediated coupling reactions were demonstrated on polystyrene (PS) resin for the preparation of cyclohexadienyl amides. Thus, treatment of a PS-supported cationic iron cyclohexadienyl complex 3 with a variety of nucleophiles such as electron-rich aromatics, amines, alcohols, and a phosphite in the presence of i-Pr₂EtN in CH₂Cl₂ at room temperature for 16 hours gave complexes 4. These resulting complexes 4 were converted via cleavage of PS supports with amines and removal of iron carbonyl with alkaline H₂O₂ into cyclohexadienyl amides 5 of 54-100% purity with 9-56% overall yields (18 examples).