Transfer hydrogenation of ketones catalyzed by ruthenium–NHC complexes 3(a–c)^a.

Entry	Substrate	Catalyst	Product	Yieldb (%)
1		3a		56
2		3b		45
3		3c		60
4		3a		64
5		3b		48
6		3c		57
7		3a		35
8		3b		25
9		3c		40
10		3a		32
11		3b		15
12		3c		28
13		3a		70
14		3b		64
15		3c		66

^aReaction conditions: 0.005 mmol Ru–NHC, i-PrOH (5 ml), KOH (2 mmol), substrate (0.5 mmol), 80 °C, 1 h.

^bConversions are based on corresponding ketones.