A Straightforward Synthesis of N‐Substituted Amino Acid Steroid Lactones via Pd‐Catalyzed Three‐Component Reactions of Steroid Enol Ethers, Glyoxylic Acid, and Anilines

ABSTRACT The Pd‐catalyzed [3 + 2] inverted demand cycloaddition between in situ‐generated α‐iminocarboxylic acids and steroid enol ethers led to a single diastereomer of amino acid steroid lactones. The combination of the steric hindrance around the reaction centers in the enol ethers and the predominance of the endo mode of the cycloaddition explains the highly diastereoselectivity observed.