Table 1.

Conditions optimization for mechanical Michael addition reaction.

Entry	Base	R1	Conditions	Conv. (%) c	Yield (%)
1	-	-	Mechano- catalysis a	2	1
2	ZnO	H	Mechano- chemistry a	10	1
3	MgO	H	Mechano- chemistry a	4	1
4	CaCO3	H	Mechano- chemistry a	0	0
5	CaO	H	Mechano- chemistry a	>99	95d
6	Eco-CaOx	H	Mechano- chemistry a	>99	84c
7	K2CO3	H	Mechano- chemistry a	94	91d
8	K2CO3	H	Batch a	98	93c
9	K2CO3 + CaO	H	Mechano- chemistry a	>99	95c
10	K2CO3 + CaCO3	H	Mechano- chemistry a	>99	93d
11	K2CO3	C5H11	Mechano- chemistry b	91	89c
12	K2CO3	C5H11	Batch b	11	0
13	KHCO3	C5H11	Mechano- chemistry b	0	0

^a 2-cyclopenten-1-one (5 mmol, 1 equiv), dimethylmalonate (5 mmol, 1 equiv), base (1 equiv), 2 h, grinding at 8.33 Hz when mechanochemistry is used. ^b 2-pentyl-cyclopenten-1-one (9.85 mmol, 1 equiv), dimethylmalonate (98.9 mmol, 10 equiv), base (1 equiv of K), 6 h, grinding at 8.33 Hz when mechanochemistry is used. ^c Conversions and yields were determined by GC-MS FID using biphenyl as an internal standard. ^d Yields were determined after distillation of the crude mixture. Pure products were characterized by NMR.