... benzyl amine in acetic acid yielded one enantiomer of N-benzylpyrrole derivative 12 in 79% yield.(27) Analogously, acid-catalyzed Paal–Knorr furan synthesis gave tetrahydrobenzofuran 13 in 76% yield.(28) The preparations of enantiorenriched 4,5,6,7-tetrahydropyrrole and ...