Table 5. Impact of reaction parameters for the synthesis of 1,4-dihydropyridine 13a.

Unless otherwise specified, the reaction was carried out with substrate 1a (0.1 mmol), 12a, and Cu(OTf)₂ in MeCN under irradiation with blue LEDs at room temperature.

Entry	12a (mmol)	Cu(OTf)2 (mmol)	MeCN (ml)	Yield (%)*
1	0.2	0.02	2	21
2	0.3	0.02	2	40
3	0.4	0.02	2	47
4	0.5	0.02	2	50
5	0.75	0.02	2	51
6	1	0.02	2	50
7	0.5	0.02	6	35
8	0.5	0.02	8	29
9	0.5	0.02	1	55
10	0.5	0.02	0.5	48
11	0.5	0.01	1	35
12	0.5	0.03	1	52
13†	0.5	0.02	1	67

*Isolated yields after purification by column chromatography.

†After the reaction was finished, 1 equiv. of NaBH₃CN was added and stirred for 1 hour.