Table 2.

Effect of leaving groups.^a

Entry	X	Copper	L*	Solvent	Additive	eeb
1	Br	CuClO4	F	CH2Cl2	B(OiPr)3	38%
2	Br	CuI	A	CHCl3		NP
3	OAc	CuClO4	F	CH2Cl2	B(OiPr)3	NP
4	OAc	CuI	A	CHCl3		NP
5	OPO(OEt)2	CuClO4	F	CH2Cl2	B(OiPr)3	77%
6	OPO(OEt)2	CuI	A	CHCl3		29%

^aConditions: 4-phenyl-1-butene (2.5 equiv), Cp₂ZrHCl (2.0 equiv), 2 (1.0 equiv), CuL*(0.1 equiv), additive (1.0 equiv), in solvent (2.0 mL), room temperature. ^bee determined by HPLC. NP = no product. For more information on procedures see Supporting Information File 1.