Regioselective and Diastereoselective (5+1)‐Annulations: Access to Functionalized Hexahydroisoindoles from Morita–Baylis–Hillman Carbonates and 3‐Aryl‐3‐Oxopropanenitriles

Moving beyond classical Morita–Baylis–Hillman (MBH) carbonates, we have developed novel pyrrolidinone‐based MBH carbonates. Owing to their dielectrophilic nature, these compounds serve as versatile C5 synthons in annulation reactions. Herein, we report their (5+1)‐annulations with 3‐aryl‐3‐oxopropanenitriles, which efficiently deliver functionalized hexahydroisoindoles using 1,8‐diazabicyclo[5.4.0]undec‐7‐ene as a bifunctional nucleophilic/base catalyst. This synthetic strategy enables the asymmetric synthesis of hexahydroisoindoles with good regioselectivity and diastereoselectivity.