Table 1. Reaction optimisation for iron- and cobalt-catalysed hydrosilylation using tetrafluoroborate pre-catalyst activation ^a .

Entry	[M]	Loading (mol%)	Ligand	Yield (%) (2a : 3a)
1	FeCl2	2	EtBIP	0
2	Fe(OTf)2	2	EtBIP	0
3	Fe(BF 4 ) 2 ·6H 2 O	2	Et BIP	87 (93 : 7)
4	Fe(BF4)2·6H2O	0.5	EtBIP	67
5	Fe(BF4)2·6H2O	1	EtBIP	82
6	Fe(BF4)2·6H2O	2	HBIP	0
7	Fe(BF4)2·6H2O	2	MeBIP	Trace
8	Fe(BF4)2·6H2O	2	MesBIP	78 (>95 : 5)
9	Fe(BF4)2·6H2O	2	iPrBIP	Trace
10	Co(BF4)2·6H2O	2	HBIP	84 (86 : 14)
11	Co(BF4)2·6H2O	2	MeBIP	72 (4 : 96)
12	Co(BF4)2·6H2O	2	MesBIP	68 (3 : 97)
13	Co(BF4)2·6H2O	2	EtBIP	82 (5 : 95)
14	Co(BF4)2·6H2O	2	iPrBIP	31 (16 : 84)
15	Co(BF 4 ) 2 ·6H 2 O	1	Et BIP	90 (8 : 92)

^aReaction conditions: 1-octene (1.00 equiv.), phenylsilane (1.10 equiv.) and metal tetrafluoroborate (n mol%), THF (1 M), r.t., 1 h. Yields determined by ¹H NMR spectroscopy of the crude reaction mixture using 1,3,5-trimethoxybenzene as an internal standard.