The present report describes an organocatalytic cascade reaction between 2-alkylidene benzo[b]thiophenone derivatives and enones in the presence of the Cinchona alkaloid amine. Spirobenzothiophenonic cyclohexane derivatives containing three stereocenters were prepared via one-step synthesis in yields ranging from 88 to 96% and in enantioselectivities (enantiomeric excess (ee)) ranging from 85 to 97%, with diastereoselectivities of approximately 14/2/1. Therefore, this method provides an efficient route for the synthesis of a new class of optically active 2-spirobenzothiophenones.

Department of Inorganic Chemistry Faculty of Science Charles University Hlavova 2030 8 128 43 Prague 2 Czech Republic

Department of Organic Chemistry Faculty of Science Charles University Hlavova 2030 8 128 43 Prague 2 Czech Republic

References provided by Crossref.org

Access to Spirooxindole-Fused Cyclopentanes via a Stereoselective Organocascade Reaction Using Bifunctional Catalysis