The First Domino Reduction/Imine Formation/Intramolecular Aza-Diels–Alder Reaction for the Diastereoselective Preparation of Tetrahydrochromano[4,3-b]quinolines

Publikations-Art

Zeitschriftenbeitrag (peer-reviewed)

Autoren

Imrich, H.-G. ; Conrad, J.; Beifuss, U.

Erscheinungsjahr

2016

Veröffentlicht in

Eur. J. Org. Chem.

DOI

10.1002/ejoc.201600976

Seite (von - bis)

5706-5715

The first domino reduction/imine formation/intramolecular aza-Diels–Alder reaction is reported. Tetrahydrochromano[4,3-b]quinolines are formed with high exo-E-anti selectivity and yields up to 87 % when a nitrobenzene and a 2-(cinnamyloxy)benzaldehyde are reacted in aqueous citric acid by using iron as a reductant and montmorillonite K10 as a catalyst. The domino process starts with the in situ reduction of the nitrobenzene to the corresponding aniline, which is followed by imine formation and terminated by an intramolecular aza-Diels–Alder reaction.