English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

The title compound, C 21 H 17 ClO 6 , is optically pure and adopts an  R  configuration. It was obtained by an organocatalytic asymmetric Michael addition of 4-hydroxy­coumarin with ( E )-ethyl 4-(4-chloro­phen­yl)-2-oxobut-3-enoate. The structure consists of a tetra­hydro­pyran unit fused to the coumarin ring  ring system. The hydroxyl and phenyl groups are on the same side of the tetra­hydro­pyrane ring. The benzene ring is almost perpendicular to the coumarin ring [dihedral angle of 72.89 (3)°]. In the crystal structure, inter­molecular O—H⋯O hydrogen bonds are observed. An intra­molecular O—H⋯O contact also occurs.

(4R)-Ethyl 4-(4-chlorophenyl)-2-hydroxy-5-oxo-2,3,4,5-tetrahydropyrano[3,2-c]chromene-2-carboxylate