Tetrahydroisoquinoline derivatives are useful synthetic intermediates,which play an important role in the preparation of natural products,pharmaceuticals and other materials.Herein,we report an unprecedented redox-neutral aza-benzoin protocol to construct such scaffold.Upon exposure of tetrahydroisoquinolines to aromatic aldehydes in the presence of an NHC catalyst,the C-1 acylated tetrahydroisoquinolines were obtained in moderate to good yields.