Table 2.

Protic Acids in the Aromatic Decarboxylation (Scheme 3)^a

Entry	H Source	pKa b	pKa c	Conv. (%)d
1	CF3CO2H	0.2	3.5	86
2	HCl	−7.0	1.8	0
3	HNO3	−1.3	NAe	61
4	CH3SO3H	−1.2	1.6	76
5	p-NO2C6H4CO2H	3.4	9.0	85
6	HCO2H (96%)	3.8	NAe	1
7	CH3CO2H	4.8	12.3	66

^aReaction conditions: initial concentration [6] = 0.09–0.11 M and [Pd(O₂CCF₃)₂] = 0.019–0.021 M, 3.0 mL 5% DMSO-DMF, 70 °C, 24 h, 10 equiv acid.

^bDetermined in H₂O.⁹⁰

^cDetermined in DMSO.⁹¹

^dGC monitoring of the formation of 8 with biphenyl as internal standard.

^eInformation is not available (NA).