Table 1 Nickel-catalyzed asymmetric reductive trifluoroalkylation of vinyl iodides: optimization of conditions^a


Entry	Ligand	Solvent	Yield (%)^b	ee (%)^c
1	L1	THF	52	64
2	L2	THF	17	–
3	L3	THF	0	–
4	L4	THF	24	77
5	L5	THF	27	85
6	L6	THF	20	88
7	L7	THF	27	90
8	L8	THF	37	93
9^d	L8	THF	51	93
10^d,e	L8	THF	59	93
11^d,e	L8	THF/DMAc (9/1)	78	91
12^d,e	L8	THF/N,N-Dimethylpropionamide (9/1)	79	92
13^d,e	L9	THF/N,N-Dimethylpropionamide (9/1)	90	95
14^d,e,f	L9	THF/N,N-Dimethylpropionamide (9/1)	81	94

THF tetrahydrofuran, DMAc dimethylacetamide, ee enantiomer excess, TBAI tetrabutylammonium iodide.
^aReaction conditions (unless otherwise specified): 1a (0.10 mmol, 1.0 equiv), 2a (0.10 mmol, 1.0 equiv), NiBr₂•DME (10 mol%), Ligand (13 mol%), Mn (0.20 mmol, 2.0 equiv), TBAI (0.05 mmol, 0.5 equiv), THF (0.5 mL), −4 °C, 20 h.
^bIsolated yields.
^cThe ee values were determined by HPLC on a chiral stationary phase.
^d2.0 equiv of 2a was used.
^e1.0 equiv of TBAI was used.
^fVinyl bromide was used instead.

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