Coumarin (III) was prepared by condensation of benzophenone (I) with phenylacetic acid (II) in the presence of Ac2O and Et3N. Reduction of the lactone function of (III) with LiAlH4, followed by acidic treatment furnished diaryl chromene (IV). Subsequent hydrogenation of (IV) over Pd/C gave rise to the racemic cis chromane (V), which was O-alkylated with 1-(2-chloroethyl) pyrrolidine (VI) producing the corresponding (pyrrolidinyl)ethoxy derivative. Resolution by means of active ditoluoyl tartaric acid yielded the desired (-)-enantiomer (VII). Finally, cleavage of the methoxy group using pyridine hydrochloride at 150 C provided the title compound.

Coumarin (III) was prepared by condensation of benzophenone (I) with phenylacetic acid (II) in the presence of Ac2O and Et3N. Reduction of the lactone function of (III) with LiAlH4, followed by acidic treatment furnished diaryl chromene (IV). Subsequent hydrogenation of (IV) over Pd/C gave rise to the racemic cis chromane (V), which was O-alkylated with 1-(2-chloroethyl) pyrrolidine (VI) producing the corresponding (pyrrolidinyl)ethoxy derivative. Resolution by means of active ditoluoyl tartaric acid yielded the desired (-)-enantiomer (VII). Finally, cleavage of the methoxy group using pyridine hydrochloride at 150 C provided the title compound.

Coumarin (III) was prepared by condensation of benzophenone (I) with phenylacetic acid (II) in the presence of Ac2O and Et3N. Reduction of the lactone function of (III) with LiAlH4, followed by acidic treatment furnished diaryl chromene (IV). Subsequent hydrogenation of (IV) over Pd/C gave rise to the racemic cis chromane (V), which was O-alkylated with 1-(2-chloroethyl) pyrrolidine (VI) producing the corresponding (pyrrolidinyl)ethoxy derivative. Resolution by means of active ditoluoyl tartaric acid yielded the desired (-)-enantiomer (VII). Finally, cleavage of the methoxy group using pyridine hydrochloride at 150 C provided the title compound.