Catalytic Enantioselective Synthesis of Ring-Fused Tetrahydroquinolines

Significance

The intramolecular hydride shift-ring closure sequence allows rapid molecular complexity generation. Unlike oxidative C-H activation protocols, this transformation does not involve ­redox processes. The authors report the first catalytic enantioselective protocol of this type providing access to tetrahydroquinolines. Under optimized conditions a number of variously substituted products were prepared in good to excellent yields (72-97%) and high enantioselectivities (up to 93% ee). Diastereomeric ratios ranged from 50:50 to 90:10.