An olefin isomerization/asymmetric Pictet–Spengler cascade via sequential catalysis of ruthenium alkylidene and chiral phosphoric acid

Chiral phosphoric acid works together with Hoveyda-Grubbs II catalyst enabling highly efficient synthesis of enantioenriched tetrahydro-β-carboline (up to 95% yield, 90% ee) through an olefin isomerization/Pictet-Spengler cascade reaction via sequential catalysis.