Table 1. Evaluation of the conditions for the Co-catalyzed hydrosilylation of 1-phenyl-1,3-butadiene ^a .

Entry	Ligand	Temperature	Conversion b (%)	Yield of 1a b (%)	1a/2a/3a b
1	PhPDI	50 °C	>99	27	31 : — : 69
2	TFAPDI	50 °C	>99	33	35 : — : 65
3	PyBox	50 °C	>99	49	56 : 4 : 40
4	dppm	50 °C	28	23	>99 : — : —
5	dppe	50 °C	78	77	>99 : — : —
6	dppbz	50 °C	9	5	>99 : — : —
7	binap	50 °C	93	76	>99 : — : —
8	xantphos	50 °C	>99	81	>99 : — : —
9 c	xantphos	rt	>99	87	>99 : — : —
10 c , d	xantphos	rt	>99	83	96 : 4 : —

^aConditions: (E)-diene (0.400 mmol), PhSiH₃ (0.500 mmol), Co(acac)₂ (12.0 μmol), ligand (12.0 μmol), and THF (1 mL) for 3 h.

^bThe conversion of diene, yield of 1a, and the ratio of products 1a, 2a, and 3a were determined by GC analysis with tridecane as the internal standard.

^cCatalyst (1 mol%).

^dA mixture of (E/Z)-1-phenyl-1,3-butadiene (E/Z = 45 : 55) was used.