The reactions of a series of alkyl X-phenylpropiolates with 2-hydroxy-1-naphthaldehyde and triphenylphosphine led to benzochromenes in moderate yields. When the reactions were performed in the presence of bis(4-methoxyphenyl)phenylphosphine instead of triphenylphosphine, the rate and yields of the reactions increased. Reaction yields were enhanced for alkyl X-phenylpropiolates when X was an electron-deficient substituent such as CF3 or Cl, thus showing that the electronic effect of substituents plays an important role in the reactions.
