Table 7. Optimization of the one-pot Sonogashira coupling/cyclopropenation mechanochemical reaction ^a .

Entry	Palladium	Vial catalyst b	Approach	Reaction time (h)	Yield c %
1	None	Stainless steel vial	1	16	0 d
2	PdCl2(PPh3)2	Stainless steel vial	1	16	0 e
3	Pd(PPh3)4 g	Stainless steel vial	1	16	0 e
4	PdCl2(PPh3)2	Nickel vial	1	16	0 d
5	PdCl2(PPh3)2	Ag foil (S.S.)	1	16	40
6	Pd(OAc)2	Ag foil (S.S.)	1	16	Trace
7	Pd(PPh3)4 g	Ag foil (S.S.)	1	16	38
8	Pd(dba)2	Ag foil (S.S.)	1	16	10
9	PdCl2(PPh3)2	Cu foil (S.S.)	1	16	0 f
10	Pd(OAc)2	Ag foil (S.S.)	2	6 + 16	Trace
11	Pd(PPh3)4 g	Ag foil (S.S.)	2	6 + 16	75
12	Pd(dba)2	Ag foil (S.S.)	2	6 + 16	60
13	PdCl2(PPh3)2	Ag foil (S.S.)	2	6 + 16	76
14	PdCl2(PPh3)2	Ag foil (S.S.)	2	6 + 12	75
15	PdCl2(PPh3)2	Ag foil (S.S.)	2	6 + 10	72
16	PdCl 2 (PPh 3 ) 2	Ag foil (S.S.)	2	6 + 8	72
17	PdCl2(PPh3)2	Cu foil (S.S.)	2	16 + 16	0 f

^aReactions conditions: diazoacetate (1 eq.), aryl halide (3 eq.), K₂CO₃ (3.5 eq.) and Pd (0.026) catalyst added in a custom made reaction vial.

^bLined metal foil in vials as active catalyst during grinding.

^cAll yields are the average of isolated yield of two experiments.

^dRecovered only starting material and small amount of dimer of diazo.

^eOnly Sonogashira-coupling product indicated.

^fMostly alkyne homo-coupling product and small amount of cyclopropenation product with terminal alkyne was observed.

^gConducted in inert atmosphere.