Solvent-Free Henry and Michael Reactions with Nitroalkanes Promoted by Potassium Carbonate as a Versatile Heterogeneous Catalyst

Table 4

Michael reactions with various nitroalkanes and Michael acceptors using 30 mol% K₂CO₃.

Entry	R1	R2	Michael acceptor	Michael adduct	Time (h)	Temperature (°C)	Yield of 8 (%)
1	H	H		8a	24	25	30
2	C2H5	H		8b	24	25	69
3 (i)	CH3	CH3		8c (i)	120	25	84
3 (ii)	CH3	CH3		8c (ii)	14	60	85
4 (i)	C3H7	H		8d (i)	72	25	79
4 (ii)	C3H7	H		8d (ii)	6	60	71
5	C5H11	H		8e	21	25	66
6 (i)	CH3	H		8f (i)	72	25	91
6 (ii)	CH3	H		8f (ii)	4	60	93
7 (i)	CH3	CH3		8g (i)	72	25	60
7 (ii)	CH3	CH3		8g (ii)	8	60	88
8 (i)	C2H5	H		8h (i)	144	25	83
8 (ii)	C2H5	H		8h (ii)	6	60	84
9	CH3	H		8i	3	60	92
10	C2H5	H		8j	14	60	89
11	CH3	H		8k	2.5	0	62
12	CH3	CH3		8l	25	25	76
13	C2H5	H		8m	4	25	57
14 (i)	CH3	H		8n (i)	24	25	Trace
14 (ii)	CH3	H		8n (ii)	24	60	Trace
14 (iii)	CH3	H		8n (iii)	10	90	47
15 (i)	C2H5	H		8o (i)	24	25	Trace
15 (ii)	C2H5	H		8o (ii)	24	60	Trace
15 (iii)	C2H5	H		8o (iii)	24	90	59
16	COOCH3	H		8p	17	90	46
17	CH3	H		8q	12	60	48

Yield of pure isolated product.
Reactions were started at 0°C for 1 hour to prevent acrylonitrile polymerization.
GC chromatograms revealed trace amounts of expected product.
CH₂Cl₂ was used as solvent as the starting acceptor was solid.