Optimization of the reaction conditions for the synthesis of benzo[b]thiophenes.

Entry	Base	Solvent	Temperature	Time (h)	Yield (%)
					9a	5a
1	NaOAc	DMF	Rt	6–8	70	Trace
2	NaOAc	DMF	100 °C	24	77	Trace
3	NaOAc	THF	Rt	6–8	67	Trace
4	NaOAc	THF	Reflux	24	72	Trace
5	TEA	DMF	Rt	3	Trace	85
6	TEA	DMF	100 °C	2	Trace	60
7	TEA	THF	Rt	6	56	Trace
8	TEA	THF	Reflux	24	63	Trace
9	K2CO3	DMF	Rt	4–6	32	40
10	K2CO3	DMF	100 °C	24	28	45
11	K2CO3	THF	Rt	6	40	20
12	K2CO3	THF	Reflux	24	43	20
13	Cs2CO3	DMF	Rt	4–6	45	20
14	Cs2CO3	DMF	100 °C	24	57	10
15	Cs2CO3	THF	Rt	6	62	Trace
16	Cs2CO3	THF	Reflux	24	64	Trace
17	Na2CO3	DMF	Rt	4–6	45	40
18	Na2CO3	DMF	100 °C	24	44	35
19	Na2CO3	THF	Rt	6	67	10
20	Na2CO3	THF	Reflux	24	52	10
21	Pyridine	DMF	Rt	4–6	10	65
22	Pyridine	DMF	100 °C	24	22	55
23	Pyridine	THF	Rt	6	56	20
24	Pyridine	THF	Reflux	24	68	20
25	TEA	DMSO	Rt	6	Trace	50
26	TEA	DMSO	Reflux	24	Trace	20