Optimization of the reaction conditions and evaluation of key parameters for the reaction selectivity^a.

Entry	Base	3aa, %	4aa, %	5aa, %	6aa, %
1	Py	0	0	90	10
2	NaHCO3	29	2	62	7
3	KOAc	44	4	47	5
4	K2CO3	70	13	7	10
5	KF	81	7	10	2
6b	tBuOK	33	5	0	62
7	DBU	85	7	3	0
8c	DBU	10	77	0	0
9c,d,e	DBU	0	0	7	93
10f	DBU	5	0	37	58
11e	DBU	0	0	0	22
12e,c	DBU	0	0	0	23
13g	DBU	0	92	0	0
14h	DBU	1	0	1	12

^aUnless otherwise noted, the reactions were carried out using 1a (0.15 mmol), 2a (0.3 mmol), DMF (3 ml), base (0.33 mmol), Eosin Y (3 mol%), 40 °C, green LEDs (1.25 W), 24 h, and argon.

^bReaction mixture was deeply colored.

^cUnder air.

^d t = 80 °C, reaction time 72 h.

^eReaction without Eosin Y and green light.

^f0.125 ml of DMF.

^gAddition of TEMPO.

^hAddition of γ-terpinene. Several reaction mixtures' NMR spectra are shown in the ESI (Fig. S1–S4).