Synthesis of trans-3-Substituted Cyclohexylamines via Brønsted Acid Cata­lyzed and Substrate-Mediated Triple Organocatalytic Cascade Reaction

t: We report a new organocatalytic cascade reaction. A combination of the amine substrate with a catalytic amount of a Bronsted acid merges enamine and iminium catalysis with Bronsted acid catalysis in a new organocatalytic cascade reaction. We found that the aniline substrate itself in combination with a catalytic amount of PTSA·H 2 O can function as an aminocatalyst accomplishing an aldol condensation-conjugate reduction cascade, which terminates in a Bronsted acid catalyzed reductive amination incorporating the amine substrate into the final product. This transformation furnishes trans-3-substituted cyclohexyl amines in good yields and good diastereoselectivities.