3‐Alkenylation of Oxindoles, Benzofuranones and Indoles from Linear Propanols

Abstract A novel organocatalytic one‐pot cascade alcohol oxidation iminium activation strategy for the 3‐alkenylation of oxindoles, benzofuranones, and indoles from substituted propanols with excellent stereo‐selectivity(E/Z up to >99:1) has been developed. This one‐pot seven‐step process involves the α ‐spirocyclopropanation of benzofuran‐2‐ones, indolin‐2‐ones, and indoles, and by adjusting the reaction temperature and base feeding, the stable α ‐spirocyclopropyl propionaldehyde intermediate was isolated.