Table 2.

Direct comparison of condensation reaction conditions.

	reaction conditions
product	Tf2O (1.2 equiv) 2-ClPyr (This work)a	POCl3 (3.0 equiv) (Ref2a)b	Oxalyl Chloride (1.1 equiv) FeCl3 (Ref2d)c	Tf2O (5.0 equiv) DMAP (Ref2c)d
	95%	23%	15%	71%
	63%	0%	9%	42%
	86%	10%	0%	63%

^aSee Figure 1 for reaction conditions.

^bPOCl₃ (3.0 equiv), xylenes, 150 °C, 3 h.

^c1) Oxalyl chloride (1.1 equiv); FeCl₃ (1.2 equiv), CH₂Cl₂, 23 °C, 12 h. 2) MeOH–H₂SO₄ (19:1), 65 °C, 1 h.

^dTf₂O (5.0 equiv), DMAP (3.0 equiv), CH₂Cl₂ 23 °C, 16 h.