Facile Access to Aldol Products from Aromatic and Heteroaromatic Aldehydes Using Ruthenium Catalyst

Table 1

Effect of the molar ratio of PPh₃ to RuCl₃⋅nH₂O on the synthesis of aldol products.

Entry^a	Catalyst (0.019 mmol)	Temp. (^∘C)	Time (h)	Yield (%)^b
1	RuCl3.nH2O	RT	3	55
2	RuCl3⋅nH2O + PPh3	RT	4	67
3	RuCl3⋅nH2O + 2PPh3	RT	3	70
4	RuCl3⋅nH2O + 3PPh3	RT	3	82
5	RuCl3⋅nH2O + 4PPh3	RT	3	72
6	RuCl3⋅nH2O + 5PPh3	RT	3	77
7	RuCl3⋅nH2O + 6PPh3	RT	4	79
8	RuCl3⋅nH2O + 3PPh3	Reflux	5.5	62
9	RuCl3⋅nH2O + 6PPh3	80	5.5	76
10	RuCl3⋅nH2O + 6PPh3	Reflux	6	65

^aAll products were characterized by ¹H NMR, ¹³C NMR, and IR data. ^bYields after purification by chromatography.