Enantioselective Synthesis of 6,6-Disubstituted Pentafulvenes Containing a Chiral Pendant Hydroxy Group

Identifier:  imarina:4123816

Handle: https://hdl.handle.net/20.500.11797/imarina4123816

Authors:  Nouch, R; Cini, M; Magre, M; Abid, M; Diéguez, M; Pàmies, O; Woodward, S; Lewis, W

Abstract:
© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Simple enantioselective synthesis of 6,6-disubstituted pentafulvenes bearing chiral pendant hydroxy groups are attained by cascade reactivity using commercially available proline-based organocatalysts. Condensation of cyclopentadiene with the acetyl function of a 1,2-formylacetophenone, followed by cyclization of a resulting fulvene-stabilized carbanion with the formyl group, generates bicyclic chiral alcohols with initial er values up to 94:6. Exceptional enantio-enrichment of the resultant alcohols results upon crystallization—even near racemic samples spontaneously de-racemize. This enables new families of substituted cyclopentadienes that are both enantiomerically and diastereomerically pure to be rapidly attained.