The transition metal catalyzed asymmetric hydrogenation of unsaturated compounds arguably presents one of the most attractive methods for the synthesis of chiral compounds. Over the last few decades, Pd has gradually grown up as a new and popular metal catalyst in homogeneous asymmetric hydrogenation the same as traditional Ru, Rh and Ir catalysts. Much progress has been successfully achieved in the asymmetric reduction of imines, enamines, olefins, ketones and heteroarenes. It was also found that palladium catalyzed asymmetric hydrogenation could be used as a key step in tandem reactions to quickly synthesize chiral compounds. This tutorial review intends to offer an overview of recent progress in homogeneous palladium catalyzed asymmetric hydrogenation and should serve as an inspiration for further advances in this area.

The conversion of furfural into cyclopentanone over Ni–Cu bimetallic catalysts was studied under hydrogen atmosphere. Furfuryl alcohol, 4-hydroxy-2-cyclopentenone and 2-cyclopentenone were verified as three key intermediates. Rearrangement of the furan ring was independent of hydrogenation, starting from furfuryl alcohol rather than furfural. The opening and closure of the furan ring were closely related to the attack of a H₂O molecule on the 5-position of furfuryl alcohol. Prior hydrogenation of the aldehyde group accounted for the different reactivity of furfural and furfuryl alcohol. The high selectivity of cyclopentanone was ascribed to the presence of 2-cyclopentenone.

Highly enantioselective hydrogenation of 3-(α-hydroxyalkyl)indoles promoted by a Brønsted acid for dehydration to form a vinylogous iminium intermediate in situ was developed with Pd(OCOCF₃)₂/(R)-H8-BINAP as catalyst with up to 97% ee. This methodology provides an efficient and rapid access to chiral 2,3-disubstituted indolines.