Table 1.

Optimization of the reaction and its conditions^a

Entrya	Additives (mol%)	Base (equiv)	Solvent	Yieldb (%)
1	Eosin Y (1%)	K2CO3 (2.0)	CH2Cl2	76
2	—	K2CO3 (2.0)	CH2Cl2	40
3	Eosin Y (1%)	—	CH2Cl2	50
4	—	—	CH2Cl2	72
5	—	—	CH2Cl2	Tracec
6	—	—	CH2Cl2	40d
7	—	—	PhCH3	Trace
8	—	—	MeCN	Trace
9	—	—	Acetone	Trace
10	—	—	Neat	95(92)e
11	—	—	Neat	n.d.f
12	—	—	Neat	80%g
13	—	—	Neat	84%h
14	—	—	Neat	86%i
15	—	—	Neat	35%j

^aReaction conditions: 1a (0.2 mmol), THF 10 equivalent, solvent 1 mL, base 2.0 equivalent, room temperature, under argon atmosphere were irradiated with 40 W LED lamp (440 nm) for 24 h.

^bYields are based on 1a, determined by ¹H-NMR using dibromomethane as the internal standard.

^cDark.

^dOpen to air.

^eIsolated yields, 1 mL THF.

^fReaction performed under 100% oxygen atmosphere.

^gOpen to air conditions.

^hUnder nitrogen atmosphere containing 1% oxygen.

ⁱPositive pressure of argon.

^jFreshly distilled THF, 24 hours, 440 nm blue LED.