Rhodium-Catalyzed Dynamic Kinetic Resolution of Racemic Internal Allenes towards Chiral Allylated Triazoles and Tetrazoles

Abstract

A general Rh-catalyzed addition reaction of nitrogen containing heterocycles to internal allenes is reported. Starting from racemic internal allenes a dynamic kinetic resolution (DKR) provides N-allylated triazoles and tetrazoles. Simultaneous control of N1/Nx-position selectivity, enantioselectivity and olefin geometry gives access to important building blocks of target-oriented synthesis. The synthetic utility is demonstrated by a gram-scale reaction and a broad substrate scope tolerating multiple functional groups. Deuterium labeling experiments and experiments with enantioenriched allenes as starting material support a plausible reaction mechanism.

Keywords

• asymmetric catalysis
• dynamic kinetic resolution
• internal allenes
• rhodium
• hydroamination