Tetrahedron

Access to racemic and enantioenriched 3-methyl-4-chromanones: catalysed asymmetric protonation of corresponding enolic species as the key step

O Roy, F Loiseau, A Riahi, F Hénin, J Muzart

Index: Roy, Olivier; Loiseau, Francois; Riahi, Abdelkhalek; Henin, Francoise; Muzart, Jacques Tetrahedron, 2003 , vol. 59, # 48 p. 9641 - 9648

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Citation Number: 23

Abstract

Brønsted acids induced the intramolecular cyclisation of 3-aryloxypropanoic esters affording 3-methyl-4-chromanones, which have been transformed into the corresponding racemic benzyl β-oxoesters. These latter esters, in the presence of hydrogen and catalytic amounts of both palladium and (endo, endo) aminoborneol, led to optically active chromanones with up to 75% ee through a deprotection–decarboxylation–protonation cascade reaction.