RuCl₃ · nH₂O as Catalyst for Diastereoselective Direct Aldol Reaction: An Efficient Route to Hormone Steroid Derivatives

Table 1

Ruthenium-catalyzed direct aldol reaction of aldehydes with progesterone at room temperature.

Entrya	Aldehyde	Yield (%)b	Time (h)	Dr (syn/anti)c
1	2a 4-ClC6H4	71	4.5	>99/<1
2	2b 3-ClC6H4	73	5	>99/<1
3	2c 4-BrC6H4	69	5	>99/<1
4	2d 4-MeSC6H4	78	5.5	>99/<1
5	2e 4-FC6H4	65	6	>99/<1
6	2f 4-NO2C6H4	58	6	>99/<1
7	2g 4-MeC6H4	69	6	>99/<1
8	2h 3-NO2C6H4	58	6	>99/<1

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