Table 2.

Optimization of reaction conditions for the synthesis of benzofurans^a.

Entry	Catalyst	Solvent	Base (mmol)	Temp. (°C)	Time (h)	Yields (%)b
						5a	4d
1	(15 mg)	Toluene	DMAP (0.5)	Reflux	12	84	Trace
2	(15 mg)	Toluene	–	Reflux	12	–	87
3	(15 mg)	–	DMAP (0.5)	100	6	92	–
4	(15 mg)	EtOH	DMAP (0.5)	Reflux	6	Trace	42
5	(15 mg)	CHCl3	DMAP (0.5)	Reflux	6	–	Tracec
6	(15 mg)	CH3CN	DMAP (0.5)	Reflux	6	Trace	45
7	(15 mg)	DCE	DMAP (0.5)	Reflux	6	Trace	37
8	(15 mg)	H2O	DMAP (0.5)	Reflux	6	Trace	20
9	–	–	DMAP (0.5)	100	6	–	–
10	(5 mg)	–	DMAP (0.5)	100	6	74	Trace
11	(10 mg)	–	DMAP (0.5)	100	6	86	Trace
12	(20 mg)	–	DMAP (0.5)	100	6	92	–
13	(15 mg)	–	DMAP (0.25)	100	6	71	24
14	(15 mg)	–	DMAP (1.0)	100	6	92	–
15	(15 mg)	–	Na2CO3 (0.5)	100	6	26	67
16	(15 mg)	–	K2CO3 (0.5)	100	6	67	Trace
17	(15 mg)	–	Cs2CO3 (0.5)	100	6	81	Trace
18	(15 mg)	–	DMAP (0.5)	60	6	65	Trace
19	(15 mg)	–	DMAP (0.5)	80	6	72	Trace
20	(15 mg)	–	DMAP (0.5)	120	6	92	Trace
21d	(15 mg)	–	DMAP (0.5)	100	6	–	–
22e	(15 mg)	–	DMAP (0.5)	100	6	–	–

^aReaction Condition: 1d (1 mmol), 2a (1.2 mmol), 3a (1.5 mmol), MIL-101(Cr)-SB-Cu. Solvents (3 mL).

^bIsolated yield.

^cDetected by TLC.

^dMIL-101(Cr)-NH₂.

^eMIL-101(Cr).