Table 2.

Optimization of the reaction conditions for the synthesis of enantioenriched chloro‐substituted allenylsilane (S)‐3 c.^[a,b]

Entry	Cat. (mol %)	Ligand* (mol %)	Base (2.0 equiv)	Solvent	T [°C]	Yield [%]	ee [c] [%]
1	CuI (10)	L1 (12)	Et3N	MeOH	−10	29	47
2	CuI (10)	L2 (12)	Et3N	MeOH	−10	7	50
3	CuI (10)	L3 (12)	Et3N	MeOH	−10	91	0
4	CuI (10)	L4 (12)	Et3N	MeOH	−10	17	10
5	CuI (10)	L6 (12)	Et3N	MeOH	−10	32	10
6	CuI (10)	L7 (12)	Et3N	MeOH	−10	68	8
7	CuI (10)	L8 (12)	Et3N	MeOH	−10	27	2
8	CuI (10)	L2 (12)	Et3N	EtOH	−10	12	40
9	CuI (10)	L2 (12)	PPD	MeOH	−10	22	52
10	CuI (10)	L5 (12)	PPD	MeOH	−10	61	60
11	CuI (10)	L5 (12)	TMP	MeOH	−10	61	66
12	CuI (10)	L5 (12)	TMP	MeOH	−30	53	74
13	CuF2 (10)	L5 (12)	TMP	MeOH	−30	60	86
14	CuF2 (10)	L5 (20)	TMP	MeOH	−30	62	90
15	CuF2 (5)	L5 (10)	TMP	MeOH	−30	62	84

[a] Reaction was run under the following reaction conditions: 1 c (0.2 mmol), 2 (0.4 mmol, 2.0 equiv), base (0.4 mmol, 2.0 equiv), 10 mol % copper catalyst, and ligand in 1.0 mL of either anhydrous MeOH or EtOH at indicated temperature under argon atmosphere for corresponding time. [b] Yield of isolated product. [c] The ee values were determined by HPLC analysis. PPD=piperidine, TMP=2,2,6,6‐tetramethylpiperidiene.