Palladium(II)-Catalyzed Oxidative Cyclization of Allylic Tosylcarbamates: Scope, Derivatization, and Mechanistic Aspects

A highly selective oxidative palladium(II)-catalyzed (Wacker-type) cyclization of readily available allylic tosylcarbamates is reported. This operationally simple catalytic reaction furnishes tosyl-protected vinyl-oxazolidinones, common precursors to syn-1,2-amino alcohols, in high yield and excellent diasteroselectivity (>20:1). It is demonstrated that both stoichiometric amounts of benzoquinone (BQ) as well as aerobic reoxidation (molecular oxygen) is suitable for this transformation. The title reaction is shown to proceed through overall trans-amidopalladation of the olefin followed by beta-hydride elimination. This process is scalable and the products are suitable for a range of subsequent transformations such as: kinetic resolution (KR) and oxidative Heck-, Wacker-, and metathesis reactions.