Organocatalyzed Asymmetric Vinylogous Michael Reactions of 3,5‐Dialkyl‐Substituted 4‐Nitroisoxazoles: A Direct Method for the Synthesis of Chiral Isoxazole Derivatives

The direct asymmetric vinylogous Michael addition of 3,5‐dialkyl‐substituted 4‐nitroisoxazoles with α,β‐unsaturated aldehydes catalyzed by a diphenylprolinol TBS ether organocatalyst is described, giving products with moderate to good yields and up to excellent enantioselectivities (96% ee). This approach provides an easy access to highly functionalized chiral isoxazole derivatives. magnified image