Optimization of base-mediated coupling between benzyl alcohol and N,N-dimethyl acetamide^a.

Entry	Base	Solvent	BnOH conversionb (%)	1 : 2 ratio	Yield of 2c (%)
1d	KOtBu (1 equiv.)	Mesitylene	100	100 : 0	0
2	KOtBu (1 equiv.)	Mesitylene	85	10 : 90	68
3	KOtBu (1 equiv.)	Toluene	80	50 : 50	30
4	KOtBu (0.2 equiv.)	Mesitylene	65	40 : 60	20
5	KOtBu (0.2 equiv.)	Toluene	60	90 : 10	<5
6 e	KOtBu (2 equiv.)	Mesitylene	100	0 : 100	85
7	KOtBu (2 equiv.)	Toluene	85	10 : 90	70
8	KOtBu (3 equiv.)	Toluene	90	0 : 100	62
9	KOtBu (2 equiv.)	Dioxane	60	20 : 80	35
10	KOtBu (2 equiv.)	Acetonitrile	50	30 : 70	20
11	KOtBu (2 equiv.)	DMF	35	80 : 20	<5
12	KOtBu (2 equiv.)	None	50	70 : 30	10
13	None	Mesitylene	0	—	0
14	NaOtBu (2 equiv.)	Mesitylene	80	0 : 100	75
15	KOH (2 equiv.)	Mesitylene	0	—	0
16	Cs2CO3 (2 equiv.)	Mesitylene	30	100 : 0	0
17	Na2CO3 (2 equiv.)	Mesitylene	0	—	0
18f	K2CO3 (2 equiv.)	Mesitylene	20	—	0
19f	NaOH (2 equiv.)	Mesitylene	90	70 : 30	10
20	NaH (2 equiv.)	Mesitylene	15	18 : 82	<5
21	KH (2 equiv.)	Mesitylene	20	10 : 90	10

^aConditions: BnOH (1 mmol), CH₃CONMe₂ (2 mmol), base, 1,3,5-trimethoxybenzene (0.5 mmol, internal standard), solvent (3 mL), reflux, 12 h.

^bDetermined by GC using the internal standard.

^cNMR yield with 1,3,5-trimethoxybenzene as the internal standard.

^dWith 5% of manganese(iii) 5,10,15,20-tetraphenylporphyrin chloride added and reaction time 48 h.

^eReaction time 6 h.

^fWith 2 mL of N,N-dimethyl acetamide.