The hydrogen bond donating ability of 1,8-naphthalenediol was investigated via a series of 1H, 13C, and 31P NMR experiments. Complexation studies using triphenylphosphine oxide and cyclohexanone as hydrogen bond acceptors revealed that 1,8-naphthalenediol is a more effective hydrogen bond donor compared to 1-naphthol and 8-methoxy-1- naphthol. Afterwards, its effectiveness as a hydrogen bonding catalyst was demonstrated in the Friedel–Crafts-type addition reaction of indole to trans-β -nitrostyrene. |
