Table 2.

Bimolecular rate constants (k, L·mol^–1·s^–1) measured for the reaction of 4-methyl-3-phenylsydnone and various acetylenes in p-cymene at 140 °C [54].

dipolarophile (disubstituted alkyne)	105k (L·mol−1·s−1)	dipolarophile (monosubstituted alkyne)	105k (L·mol−1·s−1)
MeOOC–C≡C–COOMe	2 580	H–C≡C–COOMe	823
Ph–C≡C–COPh	135	H–C≡C–CH(OPr)2	39
Ph–C≡C–COOEt	99	H–C≡C–Ph	18
Ph–C≡C–Ph	3.0a	H–C≡C–(CH2)11CH3	6.0
Ph–C≡C–Me	1.9

^aIn decaline.