Facile and Promising Method for Michael Addition of Indole and Pyrrole to Electron-Deficient trans-β-Nitroolefins Catalyzed by a Hydrogen Bond Donor Catalyst Feist’s Acid and Preliminary Study of Antimicrobial Activity

Table 2

Michael addition of indole (4) to nitroolefins 2(a–i) catalyzed by Feist’s acid.

No.	Nitroolefins (2a–i)	R = (a–i)	Products	Cat. mol%	Prod. ID	Time (h)	Yield^a(%)
1		Ph		10	7a	42	97
2		4-MePh		10	7b	42	97
3		4-MeOPh		10	7c	42	84
4		4-ClPh		10	7d	42	97
5		4-BrPh		10	7e	42	49
6^c		4-BrPh		20	7e	72	88
7		4-NitroPh		10	7f	42	55
8^c		4-NitroPh		20	7f	72	70
9		2,4-diClPh		10	7g	42	63
10^c		2,4-diClPh		20	7g	72	97
11		2,6-diClPh		10	7h	42	62
12^c		2,6-diClPh		20	7h	72	75
13^c		2-Ferrocene		20	7i	72	46

aThe reactions were performed on 0.425 mmol scale; ^bthe isolated yield after column purification; ^c20 mol% catalyst was used and reactions were run for 72 hours.