Table 1. Metal-free catalytic dehydrogenation of HCOOH/NEt₃ (5 : 2) ^a .

Entry	Catalyst (amount, mol%)	Solvent	Conv. b [%]	TON (time, h)
1	[2+ , I–] (5.0)	TDF	26	5.2 (19)
2	BBN–I (5.0)	TDF	48	9.6 (19)
3	BBN–I (5.0)	C6D6	<5	—
4	BBN–I (5.0)	Tol-d 8	<5	—
5	BBN–I (5.0)	CD3OD	<5	—
6	BBN–I (5.0)	CD3CN	84	16.8 (19)
7	BBN–H (5.0)	CD3CN	52	10.4 (19)
8	[TBDH+, 5– ] (5.0)	CD3CN	67 c	13.4 (19)
9	Cy2B–I (10.0)	CD3CN	>99 d	10 (4.5)
10	Cy2B–I (5.0)	CD3CN	>99	20 (19)
11	Cy2B–I (1.0)	CD3CN	79	79 (19), 88 (23), 100 (40)
12	[Et3NH+, 6– ] (5.0)	CD3CN	>99 c	20 (8)
13	[Et3NH+, 6– ] (1.0)	CD3CN	78 c	78 (19), 94 (23), 100 (26)

^aReaction conditions: 0.2 mmol FA, 0.08 mmol TEA, 0.2 mL deuterated solvent.

^bConversions determined by ¹H NMR using mesitylene (10 μL) as an internal standard; mean values over at least 2 runs.

^cCatalyst was recovered unchanged.

^dFull conversion reached within 4.5 h.