Table 1.

Optimization of the reaction conditions

Entry	Variation from the standard conditions	Yield (%)a
1	None	92b
2	TTP instead of 4CzIPN	<5
3	Eosin Y instead of 4CzIPN	<5
4	[Acr-Mes] + (BF4−) instead of 4CzIPN	<5
5	Rhodamine B instead of 4CzIPN	<5
6	80 °C instead of 60 °C	70
7	40 °C instead of 60 °C	69
8	DMA instead of DMSO	75
9	MeCN instead of DMSO	56
10	0.1 M instead of 0.03 M	56
11	No photocatalyst	nd
12	No light	nd

Standard conditions: 5 mol% 4CzIPN, 0.2 mmol 1a, 0.1 mmol 2a, DMSO (0.03 M), 15 W Blue LEDs, 60 °C, 5 h.

DMSO dimethyl sulfoxide, DMA dimethylacetamide, MeCN acetonitrile, nd not detected.

^aIsolated yield.

^bd.r. = 1: 1.