Highly enantioselective synthesis of chiral 3,4-dihydro-2H-pyran-5-carbonitrile via tandem Michael addition/asymmetric transfer hydrogenation/cyclization reactions catalyzed by a bifunctional NoyoriIkariya type catalyst

Tandem catalytic reaction in one-pot possesses remarkable advantages and is a powerful methodology for the synthesis of high value chemicals. Asymmetric transfer hydrogenation catalyzed by Ru-TsDPEN type catalysts, developed Noyori and Ikariya, is a useful strategy for constructing chiral alcohols and amines. Herein, a novel bifunctional Noyori-Ikariya type catalyst was developed, which displays good catalytic efficiency for Michael addition/ATH/cyclization tandem reaction. A series of chiral 3,4-dihydro-2H-pyran-5-carbonitriles were synthesized in good yield (up to 79%) and with excellent enantioselectivity (up to 97%) via this one-pot reaction under mild conditions.