Table 1. Comparison of TON and TOF for Dehydroborylation of Terminal Alkynes of Selected Substrates with Precatalysts I and III and Catalyst A.

entry	substrate	cat.	time (h)	conv. (%)	a/a′	TON	TOF (h–1)
1	1a	I	1	98	99:<1	49	49
2	1a	III	1	70	98:2	35	35
3	1a	A	5	84		16.8	3.4
4	1c	I	1.5	97	99:<1	48.5	32.5
5	1c	III	1.5	70	98:2	35	23.5
6	1c	A	5	90		18	3.6
7	1i	I	0.8	97	99:<1	48.5	60.5
8	1i	III	0.8	76	97:3	38	47.5
9	1i	A	5	81		16.2	3.2

^aReaction conditions: alkyne (0.2 mmol, 1.0 equiv.), pinacolborane (0.21 mmol, 1.05 equiv.), precatalyst I or III (1 mol %), at rt under N₂. The NMR yield was determined by ¹H NMR spectroscopy using mesitylene as the internal standard. TON and TOF were calculated for the conversion of product a. TON was calculated by dividing the number of moles of the product by the number of moles of catalyst used. TOF was determined by dividing TON by the reaction time. LZnH(I) and L′ZnH(III), calculating TON and TOF based on monomeric structures.