Collect. Czech. Chem. Commun. 2007, 72, 1046-1056

Convenient Preparation of Chiral Dipyrrolylmethanes Containing a Chiral Moiety

Pier Giorgio Cozzia,*, Sandro Gambarottab, Magda Monaria and Luca Zolia

a Dipartimento di Chimica "G. Ciamician", Università di Bologna, Via Selmi 2, 40126, Bologna, Italy
b Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada


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.

Keywords: Dipyrromethanes; Pyrroles; Calixpyrroles; Chiral ketones; Organocatalysis; Proline; Aldol condensation.

References: 51 live references.