Convenient Preparation of Chiral Dipyrrolylmethanes Containing a Chiral Moiety

Abstract

A variety of chiral bis-pyrroles have been made readily accessible via acid-catalyzed condensation of chiral ketones with pyrrole. Three representative chiral ketones 2-4 taken from the chiral pool were transformed into the corresponding bis-pyrrole derivatives in a straightforward acid-catalyzed condensation. Chiral β-hydroxy ketone derivatives, prepared through proline-catalyzed aldol condensation of acetone and an aldehyde, are readily transformed into the corresponding dipyrrolylmethane by the acid-catalyzed condensation carried out in the same conditions. The crystal structure of the chiral dipyrrolylmethane 2 derived from the (-)-menthone was determined.