Tandem Michael–Nucleouphilic Addition of 2‐Cyclopropylidene Propionaldehyde—A Novel Method for the Synthesis of Spirocyclopropane‐Annulated Heterocycles

Abstract 8‐Methyl‐4‐thia‐6‐aza‐spiro[2.5]oct‐5‐en‐7‐ols and 8‐methyl‐4‐selena‐6‐aza‐spiro[2.5]oct‐5‐en‐7‐ols were synthesized in moderate to good yields via tandem Michael–nucleophilic addition of 2‐cyclopropylidenepropionaldehyde under mild conditions.