Table 1 Optimization of the reaction conditions^a


Entry	Deviation from standard conditions	Yield^b (%)
1	none	85
2	DMSO instead of MeCN	81
3	DCM instead of MeCN	78
4	THF instead of MeCN	63
5	Cs₂CO₃ instead of Et₃N	80
6	DABCO instead of Et₃N	43
7	DBU instead of Et₃N	38
8	No Et₃N	nd
9	No HE	nd
10	Air atmosphere	<5
11	Without visible light irradiation	nd

HE Hantzsch ester.
^aUnless otherwise noted, reactions were performed with mixtures of 8 (0.05 mmol), 9 (2.0 equiv.), MeCN (0.1 M), at rt under irradiation by blue LED for 8 h.
^bYields were determined by ¹H NMR spectroscopy using 1,3,5-trimethoxybenzene as an internal standard.

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