Table 5. Metal foil-catalyzed cycloaddition of enynes with methyl phenyldiazoacetate ^a .

Entry	Enyne	Ag foil		Cu foil
		Product	Yield b (%)	Product	Yield b (%)
1			68		55
2			74		80
3			0 c		86
4			74		85

^aReaction conditions: diazoacetate (1.00 eq.), enyne (5.00 eq.) and copper foil added to a SPEX 8000M mixer/mill (18 Hz) for 16 h.

^bGC yield.

^cRecovered starting materials.