Optimization of reaction conditions^a.

Entry	Variation from “standard conditions”	Yieldb/[%]
1	None	76 (71)c
2	TBADT instead of NaDT	59
3	L1, L2 or L4 instead of L3	26, 36, 15
4	L5 or L6 instead of L3	0
5	K3PO4 instead of K2HPO4	42
6	Na2HPO4 instead of K2HPO4	27
7	MeCN instead of acetone	11
8	DCM instead of acetone	Trace
9	DMSO instead of acetone	0
10	4 equivalents of valeraldehyde were used	70
11	1 equivalent of ethyl acrylate were used	59
12	Absence of NaDT, Ni or light	0

^aReaction conditions: 1 (1 mmol), 2 (0.4 mmol), 3 (0.2 mmol), Ni(L3)Br₂ (10 mol%), NaDT (2 mol%), K₂HPO₄ (0.4 mmol) in acetone (0.2 M) at 30 °C under irradiation of LEDs (10 W, λ = 390 nm) for 24 hours.

^bGC yield with n-dodecane as internal standard.

^cIsolated yield.