Table 1.

Acidity of methyl amide complexes 2 b–e.^[a]

Entry	Complex	Ligand	Yield [%][b]	Keq[c]	(pKa)THF
1	2 b	Cp*2	33	0.249 ± 0.007	29.8
2	2 c	Cp*CpMe4	42	0.524 ± 0.010	30.1
3	2 d	CpMe42	51	1.05± 0.03	30.4
4	2 e	rac-(ebthi)	22	0.079 ± 0.005	29.3

^[a]Reactions were run with 0.3 equiv [12]crown-4.

^[b]Yield determined by NMR spectroscopy and calculated using 1,3-dimethoxy-5-methylbenzene as an external standard.

^[c]Values are reported as the average of three runs ± standard deviation.