Table 4. Metal foil-catalyzed cycloaddition of unsaturated hydrocarbons with methyl phenyldiazoacetate ^a .

Entry	R1	R2	Ag foil		Cu foil
			Yield b (%)	Product (a : b) c , d	Yield b (%)	Product (a : b) c , d
1	Ph	H	91	1 : 38 (2 : 98)	92	1 : 38 (65 : 35)
2	n-Butyl	n-Butyl (trans)	80	39 : 40 (75 : 25)	40	39 : 40 (15 : 85)
3	n-Butyl	n-Butyl (cis)	83	39 : 41 (70 : 30)	48	39 : 41 (10 : 90)
4	Ph	CH3 (trans)	90	2 : 42 (55 : 45)	86	2 : 42 (15 : 85)
5	Ph	CH3 (cis)	90	2 : 43 (55 : 45)	88	2 : 43 (15 : 85)
6	Ph	Ph (trans)	80	24 : 44 (95 : 5)	30	24 : 44 (5 : 95)
7	Ph	Ph (cis)	82	24 : 45 (90 : 10)	42	24 : 45 (5 : 95)

^aReaction Conditions: diazoacetate (1.00 eq.), alkyne (1.50 eq.), alkyne (1.5 eq.) and metal foil added to a SPEX 8000M mixer/mill (18 Hz) for 16 h.

^bGC yield.

^cDetermined by GC analysis.

^dDiastereomeric ratios were not measured.