A synthesis of ferrocenyl dihydrocoumarin and ferrocenyl dihydroquinolin-2(1H)-ones

A series of phenols have been used to react with ferrocenyl cinnamic acid, and the results of H-1 NMR and crystal structures have shown that only resorcinol and 2-naphthalenol can get ring closure products, while the others only get esterified products. This is because resorcinol and 2-naphthalenol have higher electronic density in ortho-site of hydroxyl than other phenols used in this work. Ten ferrocenyl dihydroquinolin-2(1H)-ones are synthesized by hydroarylation of ferrocenyl acrylic amides in the presence of TFA, and an interpretation is also given to the experimental fact that strong acid can not catalyze hydroarylation of acrylic anilides to dihydroquinolones.